The purpose of this 8-week research was to discuss how the intervention of instructed activity affects Regular Exercise of Behavior, Health Belief, and Exercise Self-Efficacy for elementary school students. The participants of the experiment were grade 3 and grade 4 students from Min-Tsu Elementary School of Kaohsiung City. There were 31 students in the experimental group (n=31) and 34 students in the control group (n=34) according to the purposive sampling. Two 40-minute sections of intervention of instructed activity were performed to the experimental group per week. However, intervention of instructed activity was not performed to the control group. The measurements of Regular Exercise Behavior, Health Belief and Exercise Self-Efficacy were taken before and after the experiment for both groups. The independent variables were assigned to different groups (experimental group and control group) and the action of taking measurements (pre-test and post-test). The dependent variables were assigned to the actual data collected from before and after the experiment. The collected data were analyzed by Chisquare test, and Mixed design Two-way ANOV A. This study significant level were α=.05. The following conclusions were determined from this research: 1. The number of students who have regular exercise behavior increases when instructed activity intervened. 2. The students from experimental group have higher awareness of perceived benefits of action, cues to the action, perceived susceptibility, and exercise self-efficacy. Also, the Students from experimental group have fewer barriers to take action comparing to the control group.