In this monograph the auther tried to scrutinize the criminological significance of the sentiment, “Urami” in cotext of the motives of a category of aggressive offenses, such as arson, assault and violent acts against school teachers by secondary high school students. According to Doctor Doi, “Urami” is ambivalent with “Amae”. The feeling, “Urami” is, in its passive nuance, “to tolerate and repress the discontentment caused by the inadmissible behavior of the other against one,” however, in its active nuance, “to resent and revenge,” according to the authorized Japanese dictionary. French, “ressentiment” seems to have the most similar meaning among foreign languages, but subtle passive and agressive nuance, which Japanese “Urami” keeps will never be fully expressed in other languages. The auther gave the important function as the motive of aggressive offenses to “Urami”, by studying three typical cases, which include aggression. The auther, also, testified the ambivalence between “Urami” and “Amae”, which lay under or behind the cases.