diff --git a/src/app/lib/solveProblem.ts b/src/app/lib/solveProblem.ts
index 8715fe97..2cf0c2f8 100644
--- a/src/app/lib/solveProblem.ts
+++ b/src/app/lib/solveProblem.ts
@@ -1,6 +1,7 @@
 import type { CharacterVariable, History, SolveProblemResult, Variable } from '../../types';
 
 import { Board as BoardClass } from './Board';
+import type { Character } from './Character';
 import { Character as CharacterClass } from './Character';
 
 export function parseProgram(program: string): string[] {
@@ -10,6 +11,90 @@ export function parseProgram(program: string): string[] {
     .filter((line) => line !== '');
 }
 
+export function instrumentCode(code: string): string {
+  // generateCodeからコードを受け取って、トレースできるコードを返す関数
+  const sidRegex = /\/\* (\d+) \*\//;
+  const assignmentRegex = /([\w.]+)(?: = |\+\+|--)/;
+  const modifiedCodeLines: string[] = [];
+  const lines = code.split('\n');
+
+  for (const line of lines) {
+    const trimmedLine = line.trimStart();
+    let modifiedCodeLine = trimmedLine;
+    const statementMatch = trimmedLine.match(sidRegex);
+    if (statementMatch) {
+      const sid = statementMatch[1];
+
+      // ' = 'を含むline
+      const assignmentMatch = line.match(assignmentRegex);
+      if (assignmentMatch) {
+        const variableName = assignmentMatch[1].trim();
+
+        modifiedCodeLine = modifiedCodeLine.replace(sidRegex, `log(${sid}, '${variableName}', ${variableName});`);
+      }
+    }
+    modifiedCodeLines.push(modifiedCodeLine);
+  }
+  return modifiedCodeLines.join('\n');
+}
+
+type Trace = {
+  sid: number;
+  variableName: string;
+  variableValue: Character | string;
+};
+
+export function traceCode(code: string): Trace[] {
+  const Character = CharacterClass; // eslint-disable-line
+  const Board = BoardClass; // eslint-disable-line
+  const codeForTracing = `
+const traceList = [];
+
+${code}
+
+function log(sid, variableName, variableValue) {
+  if (typeof value === 'number' && (!isFinite(value) || isNaN(value) || (modulo && value < 0))) {
+    process.exit(1);
+  }
+  traceList.push({
+    sid,
+    variableName,
+    variableValue
+  });
+}
+
+JSON.stringify(traceList);
+`.replaceAll(/\s+/g, ' ');
+  const ret: Trace[] = JSON.parse(eval(codeForTracing));
+  return ret;
+}
+
+function traceToVariablesList(traceList: Trace[]): (CharacterVariable | Variable)[][] {
+  const lineCount = traceList.at(-1)?.sid ?? 0;
+  const variablesList: (CharacterVariable | Variable)[][] = [];
+  let index = 0;
+  for (let i = 0; i < lineCount; i++) {
+    const variables = variablesList.at(-1) ?? ([] as (CharacterVariable | Variable)[]);
+    while (traceList[index].sid <= i) {
+      const { variableName, variableValue } = traceList[index];
+      const variablesIndex = variables.findIndex((variable) => variable.name === variableName);
+      if (variablesIndex === -1) {
+        if (variableValue instanceof CharacterClass) {
+          console.log('character');
+          variables.push({ name: variableName, value: variableValue } as CharacterVariable);
+        } else {
+          variables.push({ name: variableName, value: variableValue } as Variable);
+        }
+      } else {
+        variables[variablesIndex].value = variableValue;
+      }
+      index++;
+    }
+    variablesList.push([...variables]);
+  }
+  return variablesList;
+}
+
 export function executeEval(command: string): (CharacterVariable | Variable)[] {
   const Character = CharacterClass; // eslint-disable-line
   const Board = BoardClass; // eslint-disable-line
@@ -52,38 +137,36 @@ export function extractVariableNames(command: string): string[] {
 }
 
 export function solveProblem(program: string): SolveProblemResult {
-  const commands = parseProgram(program);
   const board = new BoardClass();
   const histories: History[] = [{ step: 0, characterVariables: [], board, otherVariables: [] }];
 
-  for (let i = 0; i < commands.length; i++) {
-    if (i < commands.length) {
-      let mergedCommand = '';
+  const traceList = traceCode(instrumentCode(program));
+  const variablesList = traceToVariablesList(traceList);
 
-      for (let j = 0; j <= i; j++) {
-        mergedCommand += commands[j];
-      }
+  for (const variables of variablesList) {
+    console.log('variables', variables);
+    const characterVariables = selectCharacterVariables(variables);
+    const otherVariables = selectOtherVariables(variables);
+    console.log('characterVariables', characterVariables);
+    console.log('otherVariables', otherVariables);
 
-      const variables = executeEval(mergedCommand);
-      const characterVariables = selectCharacterVariables(variables);
-      const otherVariables = selectOtherVariables(variables);
+    const board = new BoardClass();
+    for (const history of histories) {
+      if (!history.characterVariables) continue;
 
-      const board = new BoardClass();
-      for (const history of histories) {
-        if (!history.characterVariables) continue;
-
-        for (const character of history.characterVariables) {
-          board.updateGrid(character.value);
-        }
+      for (const character of history.characterVariables) {
+        board.updateGrid(character.value);
       }
-      for (const character of characterVariables) {
-        board.updateGrid(character.value as CharacterClass);
-      }
-
-      histories.push({ step: histories.length + 1, characterVariables, board, otherVariables });
     }
+    for (const character of characterVariables) {
+      board.updateGrid(character.value as CharacterClass);
+    }
+
+    histories.push({ step: histories.length + 1, characterVariables, board, otherVariables });
   }
 
+  console.log(histories);
+
   const result: SolveProblemResult = {
     characterVariables: histories?.at(-1)?.characterVariables,
     otherVariables: histories?.at(-1)?.otherVariables,
diff --git a/src/problems/problemData.ts b/src/problems/problemData.ts
index a131a84a..29cc30e7 100644
--- a/src/problems/problemData.ts
+++ b/src/problems/problemData.ts
@@ -37,19 +37,19 @@ export const courseIdToProgramIdLists: Record<CourseId, ProgramId[][]> = {
 export function generateProgram(programId: ProgramId, languageId: LanguageId): string {
   // TODO(exKAZUu): 問題IDに紐づくプログラム（テンプレート）を取得して、乱数を使って具体的なプログラムを生成する。
   return (
-    `const bear = new Character();
-bear.moveForward();
-bear.turnLeft();
-bear.upPen();
-let i = 0;
-bear.moveForward();
-const turtle = new Character({x: 3, y: 1, color: 'green'});
-turtle.moveForward();
-const foo = 'あいうえお';
-var bar = 123;
-i = i + 1;
-turtle.moveForward();
-turtle.moveForward();` || programIdToLanguageIdToProgram[programId][languageId]
+    `const bear = new Character(); /* 1 */
+bear.moveForward(); /* 2 */
+bear.turnLeft(); /* 3 */
+bear.upPen(); /* 4 */
+let i = 0; /* 5 */
+bear.moveForward(); /* 6 */
+const turtle = new Character({x: 3, y: 1, color: 'green'}); /* 7 */
+turtle.moveForward(); /* 8 */
+const foo = 'あいうえお'; /* 9 */
+var bar = 123; /* 10 */
+i = i + 1; /* 11 */
+turtle.moveForward(); /* 12 */
+turtle.moveForward(); /* 13 */` || programIdToLanguageIdToProgram[programId][languageId]
   );
 }