diff --git a/TracerOnJavassist/src/tracer/Tracer.java b/TracerOnJavassist/src/tracer/Tracer.java
index 81d7445..8358f98 100644
--- a/TracerOnJavassist/src/tracer/Tracer.java
+++ b/TracerOnJavassist/src/tracer/Tracer.java
@@ -99,7 +99,7 @@
 	private static void methodInstrumentation(final CtClass cc, final CtBehavior m) throws BadBytecode, NotFoundException, CannotCompileException {
 		// ���\�b�h�{�̓��̊e�u���b�N�̍ŏ��ɏo�͕���}������(�o�͕��̑}���Ńu���b�N�������Ă��܂��̂ŁA��ɑ}�����Ă���)
 		Block[] blocks = null;
-		if (m instanceof CtMethod) {
+		if (m instanceof CtMethod && !m.isEmpty()) {
 			ControlFlow cf = new ControlFlow((CtMethod)m);
 			blocks = cf.basicBlocks();
 			for (int i = blocks.length - 1; i >= 0; i--) {