diff --git a/AgileWorks/AgileWorks/WebView/View/SubView/SubViewStack.swift b/AgileWorks/AgileWorks/WebView/View/SubView/SubViewStack.swift
index 2329a0d8a442a4c4a799f680e15c9ce8ec31ad12..ab641f10154373acfb2631964127b07b36ff8aef 100644
--- a/AgileWorks/AgileWorks/WebView/View/SubView/SubViewStack.swift
+++ b/AgileWorks/AgileWorks/WebView/View/SubView/SubViewStack.swift
@@ -23,6 +23,8 @@ class SubViewStack: NSObject {
     }
 
     func push(_ webView: WKWebView, superView: UIView) {
+        // 回転時リサイズ設定
+        webView.autoresizingMask = [.flexibleWidth, .flexibleHeight]
         webViews.append(webView)
         webView.uiDelegate = self
         webView.allowsBackForwardNavigationGestures = true
@@ -30,6 +32,7 @@ class SubViewStack: NSObject {
         let swipeRightGesture: UISwipeGestureRecognizer = UISwipeGestureRecognizer(target: self, action: #selector(self.handleRight(sender:)))
         swipeRightGesture.numberOfTouchesRequired = 1
         swipeRightGesture.direction = .right
+        swipeRightGesture.delegate = self
         webView.addGestureRecognizer(swipeRightGesture)
         superView.addSubview(webView)
     }
@@ -77,4 +80,7 @@ extension SubViewStack: UIGestureRecognizerDelegate {
     func gestureRecognizerShouldBegin(_ gestureRecognizer: UIGestureRecognizer) -> Bool {
         return true
     }
+    func gestureRecognizer(_ gestureRecognizer: UIGestureRecognizer, shouldRecognizeSimultaneouslyWith otherGestureRecognizer: UIGestureRecognizer) -> Bool {
+      return true
+    }
 }
diff --git a/AgileWorks/AgileWorks/WebView/View/WebViewController.storyboard b/AgileWorks/AgileWorks/WebView/View/WebViewController.storyboard
index ea412d4def5377dbeae03062ef39db5471a2701a..bca840b46d55ad67828b83b8a9d527a9e2d97d55 100644
--- a/AgileWorks/AgileWorks/WebView/View/WebViewController.storyboard
+++ b/AgileWorks/AgileWorks/WebView/View/WebViewController.storyboard
@@ -20,7 +20,7 @@
                         <autoresizingMask key="autoresizingMask" widthSizable="YES" heightSizable="YES"/>
                         <subviews>
                             <view contentMode="scaleToFill" translatesAutoresizingMaskIntoConstraints="NO" id="45R-16-zHE" userLabel="Form View">
-                                <rect key="frame" x="0.0" y="0.0" width="414" height="862"/>
+                                <rect key="frame" x="0.0" y="88" width="414" height="774"/>
                                 <color key="backgroundColor" systemColor="systemBackgroundColor"/>
                             </view>
                             <view hidden="YES" contentMode="scaleToFill" translatesAutoresizingMaskIntoConstraints="NO" id="SDl-Pj-V4V" userLabel="Disabling View">
@@ -70,7 +70,7 @@
                             <constraint firstItem="SDl-Pj-V4V" firstAttribute="top" secondItem="vDu-zF-Fre" secondAttribute="top" id="R17-DV-41y"/>
                             <constraint firstItem="SDl-Pj-V4V" firstAttribute="leading" secondItem="vDu-zF-Fre" secondAttribute="leading" id="Teq-UF-56M"/>
                             <constraint firstItem="45R-16-zHE" firstAttribute="bottom" secondItem="vDu-zF-Fre" secondAttribute="bottom" id="bZu-Ip-Ko3"/>
-                            <constraint firstItem="45R-16-zHE" firstAttribute="top" secondItem="5EZ-qb-Rvc" secondAttribute="top" id="opj-Yh-EUN"/>
+                            <constraint firstItem="45R-16-zHE" firstAttribute="top" secondItem="vDu-zF-Fre" secondAttribute="top" id="opj-Yh-EUN"/>
                             <constraint firstItem="SDl-Pj-V4V" firstAttribute="trailing" secondItem="vDu-zF-Fre" secondAttribute="trailing" id="tcM-x0-S4i"/>
                         </constraints>
                     </view>
diff --git a/AgileWorks/AgileWorks/WebView/View/WebViewController.swift b/AgileWorks/AgileWorks/WebView/View/WebViewController.swift
index bae50cab81989f10fdbb52e65e9766ad878917f6..3299374b5048be8b7051e5d6dde80a48055084fc 100644
--- a/AgileWorks/AgileWorks/WebView/View/WebViewController.swift
+++ b/AgileWorks/AgileWorks/WebView/View/WebViewController.swift
@@ -18,6 +18,7 @@ class WebViewController: UIViewController {
     @IBOutlet private var closeButton: UIBarButtonItem!
     @IBOutlet private var menuButton: UIBarButtonItem!
     var mainWebView: WKWebView!
+    var subWebView: WKWebView!
     // 別ウインドウで開いたときの子ウインドウスタック
     var subViewStack = SubViewStack()
     var loadURL: String!
@@ -95,7 +96,7 @@ class WebViewController: UIViewController {
         let configuration = WKWebViewConfiguration()
         configuration.userContentController = userContentController
         configuration.applicationNameForUserAgent = kCustomUserAgent
-        mainWebView = WKWebView(frame: self.formView.frame, configuration: configuration)
+        mainWebView = WKWebView(frame: self.formView.bounds, configuration: configuration)
 
         // スクロール設定
         mainWebView.scrollView.bounces = true
@@ -418,10 +419,11 @@ extension WebViewController: WKUIDelegate {
 
     func webView(_ webView: WKWebView, createWebViewWith configuration: WKWebViewConfiguration, for navigationAction: WKNavigationAction, windowFeatures: WKWindowFeatures) -> WKWebView? {
         if navigationAction.targetFrame?.isMainFrame != true {
-            let webView = WKWebView(frame: self.formView.frame, configuration: configuration)
-            webView.load(navigationAction.request)
-            subViewStack.push(webView, superView: view)
-            return webView
+            subWebView = WKWebView(frame: self.formView.bounds, configuration: configuration)
+            subWebView.navigationDelegate = self
+            subViewStack.push(subWebView, superView: mainWebView)
+            subWebView.load(navigationAction.request)
+            return subWebView
         }
         return nil
     }
@@ -438,6 +440,132 @@ extension WebViewController: WKUIDelegate {
 }
 
 extension WebViewController: WKNavigationDelegate {
+    func webView(_ webView: WKWebView, decidePolicyFor navigationResponse: WKNavigationResponse, decisionHandler: @escaping (WKNavigationResponsePolicy) -> Void) {
+            if let attachmentFileName = attachmentFileName(ofResponce: navigationResponse),
+                let url = navigationResponse.response.url {
+                download(url: url, saveAs: attachmentFileName)
+                decisionHandler(.cancel)
+            } else {
+                decisionHandler(.allow)
+            }
+        }
+
+        private func attachmentFileName(ofResponce navigationResponse: WKNavigationResponse) -> String? {
+            guard let response = navigationResponse.response as? HTTPURLResponse,
+                let contentDisposition = response.allHeaderFields["Content-Disposition"] as? String
+                else { return nil }
+            print(response.allHeaderFields)
+            if let (fileNameStar: fileNameStar, fileName: fileName) = getAttachmentFileName(contentDisposition: contentDisposition) {
+                if let name = fileNameStar, let decoded = parseFilenameStar(name) {
+                    return decoded
+                } else if let name = fileName {
+                    return parseFilename(name)
+                }
+            }
+            return nil
+        }
+
+        private func getAttachmentFileName(contentDisposition: String) -> (fileNameStar: String?, fileName: String?)? {
+            var isAttachment = false
+            var fileNameStar: String?
+            var fileName: String?
+            for keyValue in contentDisposition.split(separator: ";") {
+                let keyValuePair = keyValue.split(separator: "=", maxSplits: 2)
+                let key = keyValuePair[0].trimmingCharacters(in: .whitespaces)
+                switch key {
+                case "attachment":
+                    isAttachment = true
+
+                case "filename*":
+                    if keyValuePair.count >= 2 {
+                        fileNameStar = keyValuePair[1].trimmingCharacters(in: .whitespaces)
+                    }
+
+                case "filename":
+                    if keyValuePair.count >= 2 {
+                        fileName = keyValuePair[1].trimmingCharacters(in: .whitespaces)
+                    }
+
+                default:
+                    break
+                }
+            }
+            if isAttachment {
+                return (fileNameStar: fileNameStar, fileName: fileName)
+            } else {
+                return nil
+            }
+        }
+
+        private func parseFilenameStar(_ encoded: String) -> String? {
+            // RFC 5987 のパターン (ややルーズ)
+            guard let pattern = try? NSRegularExpression(pattern: "^([^']+)'([^']*)'(.*)$", options: []) else { return nil }
+            let results = pattern.matches(in: encoded, options: [], range: NSRange(0..<encoded.count))
+            if results.count < 1 {
+                return nil
+            } else {
+                let result = results[0]
+                let encoding = substring(for: encoded, nsRange: result.range(at: 1))
+                if encoding != "UTF-8" {
+                    // X-point では UTF-8 のみ返すので UTF-8 のみ対応 (ほかエンコーディング対応が厄介なため)
+                    return nil
+                }
+                let name = substring(for: encoded, nsRange: result.range(at: 3))
+                return (name as NSString).removingPercentEncoding
+            }
+        }
+
+        private func substring(for str: String, nsRange: NSRange) -> Substring {
+            let first = str.index(str.startIndex, offsetBy: nsRange.location)
+            let last = str.index(first, offsetBy: nsRange.length)
+            return str[first..<last]
+        }
+
+        private func parseFilename(_ str: String) -> String {
+            // 非標準だが "" で囲まれているパターンもある
+            if (str.count >= 2) && str.hasPrefix("\"") && str.hasSuffix("\"") {
+                let first = str.index(after: str.startIndex)
+                let last = str.index(before: str.endIndex)
+                return String(str[first..<last])
+            } else {
+                return str
+            }
+        }
+
+        private func download(url: URL, saveAs fileName: String) {
+            var request = downloadRequest(url: url)
+            let tempPath: URL = FileManager.default.temporaryDirectory.appendingPathComponent(fileName)
+            Session.shared.dataTask(with: request) { data, _, err in
+                guard let data = data, err == nil else {
+                    log.e(err)
+                    return
+                }
+
+                do {
+                    try data.write(to: tempPath, options: .atomic)
+                } catch {
+                    log.e(error)
+                    return
+                }
+                DispatchQueue.main.async {[self] in
+                    subViewStack.pop()
+                    subWebView = WKWebView(frame: self.formView.bounds, configuration: WKWebViewConfiguration())
+                    subViewStack.push(subWebView, superView: mainWebView)
+                    self.subWebView.loadFileURL(tempPath, allowingReadAccessTo: tempPath)
+                }
+            }.resume()
+        }
+
+        private func downloadRequest(url: URL) -> URLRequest {
+            var request = URLRequest(url: url)
+            let formHost = KeychainDataStore().readServerURL()!
+            // WebView と同じセッションでダウンロードできるように Cookie 設定。
+            // 他サイトへのアクセス時に Cookie を漏らさないよう、ホスト名とパスを確認しておく。
+            if (url.host == formHost) && url.path.starts(with: "/AgileWorks/Broker/") {
+                request.setValue("JSESSIONID=\(KeychainDataStore().readSessionID()!)", forHTTPHeaderField: "Cookie")
+            }
+            return request
+        }
 }
 
 extension WebViewController: SubViewStackEventDelegate {