This study reviews the definition of false preparation and alteration in the crime of false preparation or alteration of public electromagnetic records(Article 227-2 of Criminal Act). Article 227-2 of Criminal Act protects the trustworthiness of the general public concerning the authenticity of public electromagnetic records, not the accuracy of information processing with electromagnetic record. Additionally in view of the fact that electromagnetic record crimes(Article 227-2 and Article 232-2 of Criminal Act) was enacted by following the form and contents of document crimes, the stand of Criminal Act which takes formalism(punishment of unauthorized preparation of document) on document crimes in principle, materialism(punishment of preparation of false document) exceptionally should be accomplished. So false preparation means to make an electromagnetic record without authority and alteration means to change the contents of a ready-made electromagnetic record without authority. This interpretation results from the systematic analyses of the penal clauses of crimes concerning documents and electromagnetic records, not from the mechanical identity of document with electromagnetic record. So I don’t agree with this judgement of the Supreme Court(2013do9003). Although we can not deny the necessity and worthiness of punishment of the preparation of false public electromagnetic record, the act of defendant cannot be punished by Article 227-2. In order to punish the preparation of false public electromagnetic records, it’s necessary to legislate a new clause. I think the terms of false preparation and alteration of public electromagnetic records are not appropriate, because these are very unfamiliar and confused with counterfeit or alteration of official document(Article 225 of Criminal Act) and private document(Article 232 of Criminal Act). So I recommend “to make an electromagnetic record without authority and to change the contents of a ready-made electromagnetic record without authority, instead of false preparation(falsification) or alteration of public and private electromagnetic records(Article 227-2 and Article 232-2 of Criminal Act). And as a result it needs to legislate a new clause that punishes the preparation of false public electromagnetic records.