시효이론은 공소시효, 형집행시효 등 형사법상 시효제도의 의미와 본질을 설명하고자 하는 것으로서, 시효가 법제도로 자리잡은 때에 시작되어 현재에 이르고 있다. 로마법에서 시효가 출발하였다는 가정에서 민사시효의 특색으로부터 형사시효의 본질을 곧바로 추론하는 이론은 민법의 청구권과 형벌권의 구별되는 특징을 간과하고 있다. 이른바 ‘시간의 힘’이론과 실체법설은 시간의 흐름에 따라서 형벌권을 이루는 대상이 사라져간다는 데에 초점을 맞추고 있는데, 그것은 형벌부과의 당위를 배제하는 이유로 충분하지 않다는 점에 한계가 있다. 오랜 시간이 흐른 이후에 소송절차가 어려워진다는 점을 이유로 한 소송법설은, 국가가 절차상의 어려움을 이유로 형벌의 의무를 스스로 포기할 수 없다는 원칙으로부터 비판할 수 있다. 실체법설과 절차법설을 결합하는 방식으로도 이러한 한계들은 극복될 수 없다. 시효의 본질은 기존 이론들이 제시한 몇 가지 요건을 통해서가 아니라, 국가 형벌권과 시간의 흐름의 관계에 대한 더 근본적인 차원의 새로운 고찰을 통해서만 파악될 수 있다.This article is mainly about a critical view on the establishment and development of theories which deal with the nature of criminal statues of limitation. The debate over this, which is one of the major theoretical arguments, is still highly issued among the studies of criminal law. Statues of limitation first appeared in Roman law and are based on the codes of civil law. Since then, scholars have supplied various arguments for the nature and general purpose of criminal statues of limitation. The question, however, is whether they are procedural or substantive. The substantive view claims that obligations according to a criminal penalty cannot be indemnified no matter how long time goes by or regardless of either procedural reasons or technical reasons. Therefore, if a person is fully reclaimed from his criminal records, there is no reason to penalize him more. In this case, statues of limitation free the culprit since it means that his records have gone into history and they do not have to be taken up any more. The procedural ground presents the idea that imposing penalty cannot be changed in time; consequently, statutes of limitation should be grounded on only procedural basis. To make it impartial, prosecution should be provided with up-to-date and reliable evidence. Hence, statutes of limitation force law-enforcement and prosecutors to apprehend wrongdoers and let them stand at the bar. There is another case which mixes two points above but adds nothing more; it just connects two different positions. Nonetheless, no assertioncan give a clear explanation about the nature of the statues of limitation. They just provoke doubts about their methods since the substantive one just has factual foundation without legal principle; procedural one has its own technical problems which prevent it from inflicting a penalty on an offender; the mixed one shows all the shortcomings in both point of views. This critical assessment comes out because these three theories lack principles with philosophical and academic stand. To secure its place in criminal law, statutes of limitationneeds a fundamental and theoretical interpretation of its nature. Otherwise, it will wander along the absurd claims from the mass that statutes of limitation should be nullified for justice.