Leadership education has been conducted for first-year students of the Master's program at the Shibaura Institute of Technology's Graduate School of Engineering and Science for over ten years. Because students have limited opportunities to learn from hands-on leadership experience, we utilize a simulator to increase students' experience in a safe environment. A student is less resistant to take leadership actions following repeated practice in simulations. The program has five modules: knowledge, training by simulation, real action, reflection, and assessment. Results of previous studies showed that student leadership ability improved. This program was popular among students because of its interesting educational method and high effectiveness. Initially this was an elective subject for a small number of students, but following its success was made compulsory and is now attended by about 80 students. It became necessary to devise a way of reflection to bring educational effects to the larger numbers of students. The e-portfolio was introduced to invite students to review their behaviour. It became difficult for the faculty to provide individual feedback on e-portfolios to so many students. Looking back on experience from others is essential for improving the students' behaviour. Consequently, we introduced peer reflection, which is evaluated in this paper - the students exchanged reflections with each other based on behaviour recorded in their e-portfolios. Consistent with our hypothesis, students who tried to continually apply the new learning obtained by peer reflection in a real situation significantly improved their leadership behaviour.