This study examined the effects of four situational factors related to bullying (ijime), i. e., the number of attackers, the relationship between the attacker and the attacked, the background of the act, and the type of the act, on children's cognition of an incident as ijime. Four hundred and sixty-eight primary school subjects and 318 secondary school subjects rated the degree to which they agreed the incidents, each of which was made by combining the four factors, as ijime. Three factors effect for primary school subjects' cognition, and all the factors effect for secondary school subjects', as well as some interactions, suggested that pupils' cognition of ijime was affected by a combination of these factors. Although primary school subjects considered the incidents as ijime more often than secondary school subjects, a particular type of act, neglect, was considered to be ijime by secondary school subjects more often than primary school subjects.