In Japanese literature and art created during the age of modernism (1920s–1930s), the fantastic and supernatural events began to occur late at night in the middle of Japan’s modern cities, especially Tokyo. This was clearly contrasting the ghost or horror story of preceding era, in which the supernatural phenomena occur during the daytime in the deep mountains or dense forests remote from the town. This essay examines how this new tendency in literary fantasies—the ephemeral and surreal events of the urban nighttime — is inspired by the alternations in nocturnal lifestyle (e.g., night theater, cabaret, nocturnal stroll in the city) accompanying the urbanization after the Great Kantō earthquake in 1923. They reflect the changes in perceptions due to some technological innovations, such as streetlamps, electric illuminations, motorcars, trains, telephones, and especially, the cinema. The surreal visions and the real cityscapes often interpenetrate and are reversed around the strolling body with unreliable perceptions. The urban nocturnal life’s novel experiences, unstable perceptions caused by new technologies, and the anxiety from the contrast between the traditional and the modern form the matrix of the novel nocturnal fantasies represented in the literature and illustrations of the modernism era.