We developed a mental healthcare system using 360° interactive video for hematopoietic cell transplant patients whose treatment is obligatory in a sterile room. This system uses projection mapping for video presentation. By using it, our aim was to allow patients to feel the spread of virtual space in aseptic rooms and to reduce anxiety and anger and to relieve stress. To assess the effectiveness of the developed system for mental care, especially in the presentation method, we executed an experiment comparing projection mapping and a monitor as a presentation tool. Twelve patients participated in the experiments. The changes in the state of patients before and after using the system were investigated. Physiological indices obtained from electrocardiography, respiration, skin conductance, scores of questionnaires, and answers in interviews were used for evaluation. Significant changes were observed between pre and post trials in the scores of STAI-Y1 and the anxiety score of VAS; however, there were no significant differences between the two presentation methods. The results of interview showed the advantage of projection mapping in the feeling of space spreading, presence, and preference to use.