Forty female Japanese college subjects exchanged shocks with a female opponent, in a competitive aggression task, who increased attack. The half of the subjects were instructed to provoke the opponent in the early phase of interactions by delivering very intense shocks, whereas they were allowed of free choice in the later phase. The results supported the hypothesis that the experimental subjects would attribute the attack which were intensified after provocation to the exogenous causes for the opponent and so they would refrained from severe retaliation more than the control subjects who would attribute the increasing attack to the opponent's endogenous causes. It was discussed that retaliation is mediated by two stages of attribution of attack: the causation of harm (the internal-external dimension) and that of aggressive intent (the endogenous-exogenous dimension).