The purpose of this study was to examine psychological factors that affect the transmission of rumor and criticism in social media during disasters. 40 students at Chiba University evaluated 10 rumor tweets and corresponding 10 criticism tweets that were posted in Twitter after the Japan March 11 Earthquake. Among some psychological factors, only importance was related to intended transmission of rumor. Surprisingly, accuracy and anxiety were not predictors of any transmission. Estimated transmission of criticisms was higher when its importance was high, while that of rumor did not vary according to importance. Interestingly, although participants estimated that criticisms were spread more than rumor, they intended to transmit rumors as much as criticisms.