diff --git a/knoda/src/B073_Illumination.java b/knoda/src/B073_Illumination.java
new file mode 100644
index 0000000000000000000000000000000000000000..f1017fb3094e93a2ba161aa78b4b3cabcd2e2513
--- /dev/null
+++ b/knoda/src/B073_Illumination.java
@@ -0,0 +1,68 @@
+package hellojunit;
+
+import java.util.ArrayList;
+import java.util.List;
+import java.util.Scanner;
+
+public class B073_Illumination {
+
+	public static void main(String[] args) {
+		final Scanner scan = new Scanner(System.in);
+		final int treeNum = scan.nextInt();
+		final int baseLightBulbNum = scan.nextInt(); // 安全基準を満たす電球の個数
+		List<Integer> lightBulbList = new ArrayList<Integer>(); // それぞれの木に存在する電球の個数
+		for (int i = 0; i < treeNum; i++) {
+			lightBulbList.add(scan.nextInt());
+		}
+		final int sectionNum = scan.nextInt(); // 電球の数を調査したい区間の数
+		
+		// 電球を調査したい区間の始点と終点を格納したリスト
+		final List<List<Integer>> sectionList = new ArrayList<List<Integer>>();
+		
+		for (int i = 0; i < sectionNum; i++) {
+			final List<Integer> section = new ArrayList<Integer>();
+			section.add(scan.nextInt()); // 始点
+			section.add(scan.nextInt()); // 終点
+			sectionList.add(section);
+		}
+		final IlluminationSearch illuminationSearch = new IlluminationSearch();
+		// それぞれの木に存在する電球の個数を取得する
+		lightBulbList = illuminationSearch.getLightBulbList(lightBulbList, sectionList, baseLightBulbNum);
+		for (int i = 0; i < lightBulbList.size(); i++) {
+			System.out.print(lightBulbList.get(i));
+			if (i != lightBulbList.size() - 1) {
+				System.out.print(" ");
+			}
+		}
+		scan.close();
+	}
+
+}
+
+class IlluminationSearch {
+	private final int START_INDEX = 0;  // 始点の要素番号
+	private final int FINISH_INDEX = 1; // 終点の要素番号
+	
+	// それぞれの木に存在する電球の個数を取得するメソッド
+	public List<Integer> getLightBulbList(final List<Integer> lightBulbList, final List<List<Integer>> sectionList,
+			final int baseLightBulbNum) {
+		
+		// それぞれの区間で、追加する電球の個数を算出する
+		for (final List<Integer> section : sectionList) {
+			int sum = 0;
+			int average;
+			// ある区間の電球の平均個数を算出する
+			for (int i = section.get(START_INDEX) - 1; i <= section.get(FINISH_INDEX) - 1; i++) {
+				sum += lightBulbList.get(i);
+			}
+			average = sum / (section.get(FINISH_INDEX) - section.get(START_INDEX) + 1);
+			// 平均個数が安全基準を満たす電球個数に達していないとき、区間に存在するすべての木に足りない電球分を追加する
+			if (average < baseLightBulbNum) {
+				for (int i = section.get(START_INDEX) - 1; i <= section.get(FINISH_INDEX) - 1; i++) {
+					lightBulbList.set(i, lightBulbList.get(i) + (baseLightBulbNum - average));
+				}
+			}
+		}
+		return lightBulbList;
+	}
+}
diff --git a/knoda/test/B073_IlluminationTest.java b/knoda/test/B073_IlluminationTest.java
new file mode 100644
index 0000000000000000000000000000000000000000..b94703e963cfbe3a088cb1a14025dd6798a42da9
--- /dev/null
+++ b/knoda/test/B073_IlluminationTest.java
@@ -0,0 +1,62 @@
+package hellojunit;
+
+import static org.hamcrest.CoreMatchers.*;
+import static org.junit.Assert.*;
+
+import java.util.ArrayList;
+import java.util.Arrays;
+import java.util.List;
+
+import org.junit.Test;
+
+public class B073_IlluminationTest {
+
+	@Test
+	public void 電球が追加されるテスト() {
+		List<Integer> electricList = new ArrayList<Integer>(Arrays.asList(4, 3, 6, 1, 3));
+		final List<List<Integer>> selectionList = new ArrayList<List<Integer>>(Arrays.asList(
+				new ArrayList<Integer>(Arrays.asList(1, 3)),
+				new ArrayList<Integer>(Arrays.asList(1, 5)),
+				new ArrayList<Integer>(Arrays.asList(2, 3))));
+		final int baseElectricNum = 6;
+		IlluminationSearch illuminationSearch = new IlluminationSearch();
+		final List<Integer> actualList = illuminationSearch.getElectricList(electricList, selectionList, baseElectricNum);
+		final List<Integer> expectedList = new ArrayList<Integer>(Arrays.asList(8, 7, 10, 3, 5));
+		for (int i = 0; i < actualList.size(); i++) {
+			assertThat(actualList.get(i), is(expectedList.get(i)));
+		}
+	}
+	
+	@Test
+	public void 電球が追加されないテスト() {
+		List<Integer> electricList = new ArrayList<Integer>(Arrays.asList(4, 3, 6, 1, 3));
+		final List<List<Integer>> selectionList = new ArrayList<List<Integer>>(Arrays.asList(
+				new ArrayList<Integer>(Arrays.asList(1, 3)),
+				new ArrayList<Integer>(Arrays.asList(1, 5)),
+				new ArrayList<Integer>(Arrays.asList(2, 3))));
+		final int baseElectricNum = 3;
+		IlluminationSearch illuminationSearch = new IlluminationSearch();
+		final List<Integer> actualList = illuminationSearch.getElectricList(electricList, selectionList, baseElectricNum);
+		final List<Integer> expectedList = new ArrayList<Integer>(Arrays.asList(4, 3, 6, 1, 3));
+		for (int i = 0; i < actualList.size(); i++) {
+			assertThat(actualList.get(i), is(expectedList.get(i)));
+		}
+	}
+	
+	@Test
+	public void 電球の基準値と平均値の比較に関する境界値テスト() {
+		List<Integer> electricList = new ArrayList<Integer>(Arrays.asList(4, 3, 6, 1, 3));
+		final List<List<Integer>> selectionList = new ArrayList<List<Integer>>(Arrays.asList(
+				new ArrayList<Integer>(Arrays.asList(1, 3)),   // average:4, baseElectricNum:4
+				new ArrayList<Integer>(Arrays.asList(1, 5)),   // average:3, baseElectricNum:4
+				new ArrayList<Integer>(Arrays.asList(2, 3)))); // average:5, baseElectricNum:4
+		final int baseElectricNum = 4;
+		IlluminationSearch illuminationSearch = new IlluminationSearch();
+		final List<Integer> actualList = illuminationSearch.getElectricList(electricList, selectionList, baseElectricNum);
+		final List<Integer> expectedList = new ArrayList<Integer>(Arrays.asList(5, 4, 7, 2, 4));
+		for (int i = 0; i < actualList.size(); i++) {
+			assertThat(actualList.get(i), is(expectedList.get(i)));
+		}
+	}
+
+}