The present study examined the determinants of people's attitudes toward the Japanese government's income inequality policies. We focused particularly on people's perceived inequality of opportunity and self-perceptions of social class, and their effects on the perceived responsibility of income inequality. General survey data of 798 individuals indicated that when people perceive education/work opportunities as generally controllable through personal ability and effort, they attribute both onset and offset responsibilities more to the poor and less to the government, consequently showing less support for government intervention. Moreover, people's perception of social class moderated how they view opportunity: only among low-class respondents did the perception that opportunities are influenced by one's parents' income or their gender lead to the perception that opportunity is uncontrollable. High-class individuals, on the other hand, perceived the effects of parental income and gender on opportunity to be independent of the controllability of opportunities, suggesting that they believe that ability and effort hold strong power over general opportunity.