PURPOSE: To provide an indirect illumination device with no difference in light and darkness without throwing the shape of a light source on a reflection plate by installing a light diffusing member which diffuses the light given off from the light source between the light source and the reflection plate of indirect illumination and which throws it on the reflection plate.

CONSTITUTION: When a fluorescent lamp 17 which illuminates the bottom lower part of an escalator is turned on, the light given off from the fluorescent lamp 17 passes through a transparent acrylic plate 19 and is diffused by the transpar ent acrylic plate 19. The diffused light is thrown on a reflection plate 16 and reflected from the reflection plate 16 for indirect illumination. Since the light given off from the fluorescent lamp 17 is diffused by the transparent acrylic plate 19 and is thrown on the reflection plate 16, it is possible to provide uni form illumination with no difference in light and darkness without throwing the shape of the fluorescent lamp 17 on the reflection plate 16.