What are the benefits of negative thinking and negative affect? Although previous studies in evolutionary psychology, social psychology, and clinical psychology have clarified the question, there has been no definitive study asking people directly about the perceived benefits. In the present study, 119 Japanese undergraduates were asked how they recognized the benefits of negative thinking and negative affect. Their answers were analyzed qualitatively. The answers were arranged into 30 smaller categories and 12 superordinate ones. The benefits were divided into "benefits to the self" and "benefits to interpersonal relations." Finally, the conditions necessary for the negative thinking and negative affect being benign, and possible cultural differences, were discussed.