This study is an empirical study about the effects of perceived risks and perceived benefits on purchase intention in mobile commerce. Perceived risks and perceived benefits are proposed as mediators that make a significant impact on purchase intention in mobile commerce. Also, this study compared the direct effect of perceived risks, perceived benefits and consumer subjective knowledge to purchase intention. As antecedents of perceived risks and perceived benefits, subjective knowledge, mobile Internet familiarity, credibility for the purchase and provided information level are proposed and verified. Results from this study are as follows: First, the effect of perceived risks to purchase intention is not significant whereas that of perceived benefits is significant. Second, this study revealed that mobile Internet familiarity, credibility for the purchase and information level are significantly related to mobile purchase intention through perceived benefit. Third, subjective knowledge makes a significant impact on purchase intention directly not mediated by perceived risk or perceived benefit. Based on these results, managerial implications for mobile commerce vitalization and marketing strategy are discussed. Finally, limitation for this research and further research issues are suggested.