This study examined the effects of elaboration on recipients′ attitude change process when persuasion was by two individuals with different opinions. Dual-process model of persuasion explains that recipients change their opinions based on argument quality in high elaboration conditions, but attitude change is based on peripheral cues (e.g., group membership) in low elaboration conditions. The model assumes a situation in which one person persuades another. In study 1, 46 participants read two persuasive messages from in/out-group members, which were manipulated for argument quality, and evaluated their attitudes. Results showed participants read messages carefully and changed their attitudes based on argument quality. In study 2, 65 participants were randomly assigned two elaboration conditions (w/wo time constraints in reading both in/out-group members′ messages). Results showed participants changed their attitudes toward the in-group member in low elaboration conditions. Dual-process model of persuasion was found applicable for persuasion by two individuals with different opinions.