This paper treats the conversions of a former executive member of Aum Shinrikyo. He was a spiritual seeker and visited various religious groups and psychics when he was young. Then he met Asahara Shoko, and thought that he had found an authentic guru, and became the first member of Aum Shinrikyo to renounce the world. He actively committed himself to various activities of the religious organization for the supposed-to-be salvation of mankind, motivated by his firm belief and mystical experiences. He was also inevitably involved in its criminal activities at the same time. On the one hand, when he had strong faith the murderous act by a religious group could be religiously justified and rationalized as salvation through "poa"; on the other hand, when it resulted in apostasy, he had to suffer from unbearable regret from having been involved in homicide, plain and simple, and other crimes.