The purpose of this study was to examine students' interaction in "Free time" at elementary science class. As the result of analyzing the protocol of the discussion activities, it became clear that students visited other group to confirm the contents of discussion, and students tried to invite the student of other group to the own group and to make the contents of discussion confirmed. It also became clear that students formed new learning groups, discussed actively and solved their problems. In addition, it was recognized that students sometimes couldn't speak questions they had in their minds, but when they got the same opinion from students in other groups, they could speak up, and that students from different groups gathered at the other group and confirmed their contents each other. As the result of analyzing the questionnaire, most students who seldom had spoken in the whole class could discuss in "Free time".