While some previous researchers have found that guilt encourages prosocial behaviour towards a victim at the expense of other people, others have found the opposite, that is, people allocate resources at the expense of themselves. The present research used a hypothetical scenario method to determine which of these patterns would be replicated in the collectivistic context of Japanese society. In addition, we separated the cause of feelings of guilt into having caused harm and being at fault, and examined in more detail the effect of guilt on prosocial behaviour. Our results show that, in line with the second set of previous researchers, participants who were induced to feel guilt for having caused harm were more likely to allocate their resources to their victim at the expense of themselves than were individuals in the no-harm condition. This suggests that differences in social context influence the effect of guilt on prosocial behaviour in different ways.