The purpose of this paper is to examine what kind of mechanism exists behind recent government decisions concerning food-borne risks in Japan. To fulfill this purpose, a conceptual model was built and applied to the contemporary Japanese political situation. Three major findings of this study are as follows: First, theoretically, excessively sensitive response to food-borne risks can be explained by the behavioral pattern presented by the Prospect Theory. There is a high possibility that politicians may magnify such consumer response if they act primary to maximize their probability of being re-elected. Secondly, when a food-borne risk is of great concern, it is possible that the politically optimum level of adopted preventive measures regarding food safety would be not only higher than the socially optimal level but also higher than the optimal level for the average consumer. On the other hand, when such concerns fall out of public eye, the outcome is the opposite. Finally, in Japan, the lack of staff with scientific expertise in consumer groups and that of such expertise among politicians' staff cannot restrain consumers from excessive responses. The administrative reform complying with the recommendation of CODEX and the general political shift may also make the matter worsen. Consequently, it is highly possible that the subjective probability perception bias in Japan is becoming greater than other countries.