The purpose of this study was to compare Japanese university students' powers of explanations of three models regarding influencing factors of environment-conscious behaviors (behavioral intentions). The three models compared were the collective protection motivation model, the model regarding environment-conscious behaviors and those determinants, and the model of psychological processes leading to behavior. Three hundred and seventyeight university students answered questionnaires regarding five environment-conscious behaviors for three environmental problems. Environment-conscious behaviors for the problem of dioxin were separating waste according to type and not buying products made from polyvinyl chloride, for the problem of water pollution was using the proper amount of detergent, and for the problem of waste were refusal to over wrapping and taking part in recycle activities. As shown in the previous study to Chinese people (Yu et al., 2006), results showed that the collective protection motivation model and the model regarding environment-conscious behaviors and those determinants had nearly the same powers of explanations, and the model of psychological processes leading to behavior had a smaller power of explanation. In all three models, the powers of explanations for Japanese university students were more than two times stronger than that of Chinese university students.