The purpose of this study was to review the literature on “I-experience,” which was first investigated by Bühler（1921）. I-experience is an important phenomenon, because it is deeply related to the establishment of “I: Self as knower”（James, 1892）. Nevertheless, little attention had been given to I-experience for a long time, because of historical factors and difficulties studying a subjective experience. In Japan, interestingly, several studies have been conducted on I-experience over the past few decades. They began with a report by the clinical psychologist Nishimura（1978）, who discussed the concept of “I-experience” and was concerned with the crisis aspect of I-experience, that is, it influenced the establishment of the “I”; however, it also caused confusion and was related to depersonalization. After this proposal by Nishimura, empirical studies using questionnaires or semi-structured interviews were initiated. There was some confusion, because each researcher had a different point of view. In this article, I attempted to examine each viewpoint and share my thoughts. For one thing, I proposed that it is important to note the physical sensation involved in I-experience, because many people who had anI-experience remembered vivid sensations and that it was not a conceptual phenomenon. For another, it is necessary to examine what happens in the narrative of an I-experience from the viewpoint of clinical psychology, because it is possible that I-experience involves a traumatic memory.