The nature of illegality as referred to in criminal law lies in the opposition value of the act and opposition value of the result, and the assessment of such illegality is conducted in the manner of understanding the relationship of attribution between the two to confirm the results caused thereby after examining behavioral attributes objectively shown first. In other words, the matter which ought to be considered first to determine illegality under criminal law is the illegality of an act. When determining whether a person defamed another by publicly alleging facts, the illegality of such act ought to be determined based on the person who committed such act. Determining publicity depending on whether there is a possibility of propagation on the basis of the relationships among a person who alleged fact (a doer), the other party, and the victim does not accord with the evaluation method as mentioned above. This is because illegality on the part of a doer is determined on the basis of his/her act but in consideration of the position or role of the third person who subsequently heard the facts. In cases except for crimes including criminal defamation, etc. that regard publicity as a constituent element, whether a crime is constituted is not determined depending on the position or role of the third person, which is not an act of a doer as above. Even in the case where there is no saying what kind of relationship the third person who heard the fact alleged by a doer has with the victim, determining publicity according to such circumstance lies beyond the scope of the doer’s possibility of foresight. This renders it difficult for a doer to expect whether there is possibility to be propagated to many and unspecified persons at the time of such act. The Criminal Act does not have the general constituent elements to punish an infringement of and danger to all relevant legal interests, and regards only specific acts corresponding to constituent elements of a crime as subject to punishment. However, the theory of propagation possibility disregards the assessment of illegality concerning specific acts stipulated as constituent elements of criminal defamation, i.e., an act of publicly alleging facts, by placing emphasis on the results such as the reputation infringement or occurrence of such danger. In this respect, the theory of propagation possibility can be seen to be based on the opposition value of the result to determine the illegality of criminal defamation. In a case where a person who disclosed such facts first repeats an act of alleging facts to a particular minority, the requirements for publicity can be seen to be satisfied. However, in the case where the other party who heard the facts defaming another from