To provide a staircase lighting device of which light is made to come out from both the top face and the rising face of staircase treadboards.

Light sources 8 such as light-emitting diodes and incandescent lamps are set at a bottom part of a nonslip board 3 fitted at a front edge of each treadboard 2 of a staircase 9 for radiate light on the front side in the horizontal direction and on the top face of the nonslip board 3. On stepping down the staircase 9, one can confirm a stepping width with light form the top face as an eyemark, and on stepping up the staircase 9, one can confirm the stepping width with both light from the front side in the horizontal direction and light from the top face. Further, the light sources of light emitted from the front side in the horizontal direction and that emitted from the top face of the nonslip board can be made common, in which structure, light can be emitted from one light source in two directions of upward and sideways.