Background: Early interventions for depression among youth are greatly needed. Although Youth Mental Health First Aid (YMHFA) program has been developed to teach the public how to help young people with mental disorders, including depression, it has assumed human altruism and overlooked the possibility that participants would experience conflict between the costs and benefits of helping behaviors. The present qualitative study, therefore, initially explored content of the costs and benefits perceived by youth in terms of helping their peers with depression. Methods: A total of 56 Japanese undergraduates (32 female, 24 male; M age = 20.20, SD = 1.09) participated in the face-to-face survey. They were provided with basic knowledge about helping behaviors and were presented with a vignette describing an undergraduate with depression. Then, they left free descriptive comments on their views of the costs/benefits of helping/not helping the person in the vignette. As supplemental quantitative analyses, we statistically compared numbers of labels (n = 624), which were obtained from participants' comments, across two (costs/ benefits) × two (helping/not helping) domains. Finally, we conducted a qualitative content analysis that combined inductive and deductive methods to categorize these labels. Results: The supplemental quantitative analyses (i.e., ANOVA and post hoc analyses) on the numbers of labels highlighted that the participants perceived suppressors (i.e., costs of helping, benefits of not helping) as well as motivators (i.e., costs of not helping) in making decision to help peers with depression. The qualitative content analysis mainly showed that: (i) the categories in each domain covered multiple facets of costs and benefits, including negative/positive effects on the participants themselves, the person in the vignette, and interpersonal relationships; and that (ii) the participants perceived the conflicts of costs and benefits regardless of whether they help their peers with depression. Conclusions: These results provide evidence for how young people experience the conflicts between the costs and benefits of helping behaviors toward their peers with depression and reveal specific content of these costs and benefits. These findings could serve as a basis for extending YMHFA programs and designing educational content to promote public helping behaviors in realistic situations.