It is called "Proustian Experience" to recall our memory triggered by odor. Indeed, research into the neuroscience of olfaction suggests that this sort of memory correlates highly with the experience of emotion. In the context of folk culture, odor is considered to relate to the underworld. Moreover, smells have been considered to function as more powerful, as stimuli, than other sensory experiences in the precipitation of the flashback experiences associated with Post-traumatic Stress Disorder （PTSD）. This presentation investigates the Proustian Experience by drawing on both research and an individual case study. From the research, we could see Proustian experience from five perspectives; the affection, the psychic distance between now and then, the feeling of connection between the odor and the memory,unexpected feeling, and the feeling of wonder and impression. The subject of the case study reported that she had been shaken to the core when she had had the Proustian Experience; her experience in this instance resembles psychological constructions of shifting ego states.