Yamagishi and colleague showed that behavior favoring the in-group and trust of in-group members are based on the expectation of generalized exchange. We successfully tested a related prediction that people show stronger trust of in-group members than of out-group members in the faith game but not in the trust game. We argued that the direct exchange aspect inherent in the trust game suppresses expectations of generalized exchange taking place in the group. We conducted an experiment with 79 Japanese and 83 Australian participants. In the trust game, 27 of the 82 participants trusted the in-group trustee, while 29 trusted the out-group trustee. In the faith game, in which the expectation of generalized exchange was intact, 47 of the 80 participants trusted the in-group trustee and 37 trusted the out-group trustee. These results support our argument that expectations of generalized exchange, not in-group stereotypes, are the source of in-group trust. No cultural differences were observed between Japanese and Australian participants.