正當防衛是合法權利，然而權利不可滥用。不具防衛意思之防衡行爲可否認爲行使權利之防衡行爲，不無疑問， 學者對此曾經激烈討論。其關鍵點即在於犯罪成立三要素之結構應屬如何。依照客觀主義之理論，應就外部行爲判斷 犯罪之成立與否，則容許不具防，意思之防衡行爲成立正當防衡。但主觀主義者認爲必須有防衛意思始能成立正當防 衛。而防衡意思必要説今已成爲德國、曰本及我國之通説，甚至許多仍持客觀主義説者亦赘成防衡意思，只不過有時 難以自圓其説。惟主觀客觀説者孰優孰劣，仍須靜待發展以證之。

Self-defense is a lawful right. But the lawful right should not be abused. It is therefore doubtful whether the conduct of defense without the will of defense can be thought a lawful defense. About this guestion there were many discussions. The decisive point is the point about the structure of the three elements of Crime. According to the objective theory we must judge, only from an outside act, whether it is a crime or a justxification. This theory allows that the defense without the will of defense is also a lawful defense. But according to the subjective theory it is necessary for the self-defense to have the will of defense. And today in Germany, Japan and in our country it is already the current theory, that the will of defense is necessary. Even if many objectivists also agree to this theory. Only they have not enough reason to support their conclusion. Thus we must wait till we can testify which theory is better.