The purpose of this study is to provide the basic data to activate the operation of the volunteer activities. The specified subjects for this study are how different is it in the changes of the self-concept and the satisfaction and the intention of the continuance of volunteer activities according to the type of volunteer work and guiding organization for middle school students. For this study, 64 students, the homogeneous ability group, were intentionally assigned in the preliminary inspection of self-concept and 16 students were randomly allocated respectively for 4 groups. The consequences based on the result are as follow: First, it has more influence with the group activities than the individual on the changes in the self-concept. But, there isn`t meaningful difference by each guiding organization. Therefore, the school has to provide with activating middle school student`s activities by developing various weekly and monthly club volunteer activities. Second, for the satisfaction and the intention of continuance among the guiding organization, it has meaningful difference in the group activities only, not in the individual ones. It gives the ground for the government to provide intensified support to the leaders of the group and grant the incentives to the group of distinguished activities, in the perspective of developing sociality, promoting the group volunteer activities.