In this article, results of studies on the process of maintaining anger are described, and experimental research examining the effectiveness of the structured writing method for reducing anger is reviewed. Our research has indicated that the key factor in the process of maintaining anger is “the sense of unintegration of thoughts.” Anger is prolonged by this sense, because it mediates avoidance behaviors and recurrent thinking. Our research has also indicated that to reduce anger, it is crucial to integrate and organize thoughts about anger-evoking events by eliciting “perspective taking,” and the “need for self-change.” Moreover, it has been demonstrated that “the structured writing method,” developed on the basis of research into the process of maintaining anger, was more effective for reducing anger than traditional expressive writing methods. Participants tend to change how they talk about an event with others and decrease the number of negative words after engaging in structured writing. These findings suggest that taking various perspectives, including other’s feeling, and possible self-improvements into consideration in the structured writing method facilitates reappraising the relationship between the self and others, which in turn inhibits intrapersonal, interpersonal, and intergenerational processes of maintaining anger.