As our Statute of Criminal Procedure compels the appellant to file statement of reason for appeal, the court is to hand down ruling of rejection without reviewing the merits of the case when the appellant fails to file statement of reason for appeal. However despite the appellant's negligence to file that statement, the court is obliged to review the case as far as the case involves the issues to be investigated ex officio. The case at issue not merely shows that it does not suffice for the prosecutor to just claim 'error in fact', 'error in legal principles' or 'the intent to modify the indictment' without elaborating on grounds for appeal when filing statement of reason for appeal, but also informs that the court cannot hand down ruling of rejection without reviewing the merits of the case once the appellant has filed statement of reason for appeal, which does not meet the requirement. While the Statute of Criminal Procedure remains silent concerning the scope and limit of ex officio investigation, the Supreme Court defines the issues to be investigated ex officio as issues the court is obliged to investigate regardless of the parties' claims, such as misapplication or misunderstanding of statutes. As the Court's definition is too vague, it serves too little. It will be useful to categorize the issues to be investigated ex officio. The Court seems to be indifferent in drawing a clear line between the issue to be investigated ex officio pursuant to Art. 361-4 Para. 1 and the issue to be examined ex officio pursuant to Art. 364 Para. 2. However it is desirable to distinguish the former from the latter since each has its own ground, conditions or legal effect.