The purpose of this study was to examine the effect of camp experience upon self-concept and the factors that were changed self-concept in the high-school student who participated in a 4-days camp conducted in 1999. The subjects were 94 male students. To measure Self-concept, t he Self-Actualization Scale was administered at the beginning and the end of the camp. To measure the factors that were changed self-concept, t he questionnaire including 25 items was administered. The following results were obtained; 1) The camp participants improved in self-concept, particularly in the category of Achievement Motivation and Self-Effort, between the beginning and end of the camp. 2) Five factors that were changed self-concept were obtained; outdoor party, adventure program, camp experience, nature experience, and communication. 3) The high group of evaluated the factors that were changed self-concept showed significantly higher self-concept than low group. The high group of evaluated the factors of outdoor party and communication showed higher self-concept in sub-scale of Self-Effort than low group