Japanese and Canadian laws regarding sexual assault vary in the degree to which they incorporate the concept of sexual consent, with Japanese law being less consent-oriented than Canadian law. Although the Japanese law has incorporated the concept of sexual consent in the 2023 amendment, the public understanding of the concept is still limited. Reflecting such difference, it could be expected that the general public in both countries also differ in their perceptions and attitudes regarding punishment of sexual crime and sexual consent. The present study aimed to test these expectations and further examine the mediational mechanism that explains the national difference between Japan and Canada. The data from 1125 Japanese and 1125 Canadian respondents showed that Japanese respondents were less likely to perceive the imposition of punishment on an alleged perpetrator described in scenarios as appropriate. In contrast, the difference in the perceived victim’s consent was significant only in three out of seven scenarios. The relation between nations (Japan vs. Canada) and perceived appropriateness of punishment was mediated by the perceived victim’s consent.