This study investigated the relationship between binge-purge episodes and the affective state by analysing the changes in affective states during the binge-purge cycle. Thirty-seven Japanese patients with bulimia nervosa were surveyed for 22 types of affective states. Some negative affects were alleviated by bingeing or purging, while others were exacerbated by these behaviours. These findings suggest that one has to differentiate the temporal situations in the binge-purge cycle in considering the relationship between the affective states and binge-purge behaviours. The escape hypothesis and hopelessness hypothesis proposed by Beebe (1994) suggest some possible mechanisms. Binge and purge behaviours should be examined separately as defence functions to regulate negative moods and as acting out in response to intense negative affects.