PURPOSE: To enable light distribution over entire width of ascending stairs and descending stairs across width of a linear light source by a method wherein a reflecting surface for reflecting light to ascending stairs from a linear light source and a reflecting surface for reflecting light toward descending stairs of a reflecting board are arranged vertically.

CONSTITUTION: Translucent parts 11, 12 are formed on a front face of an apparatus 10. A reflecting board 13 is placed inside the apparatus 10 and a linear light source 14 is mounted in a horizontal posture in front of the reflecting board 13. An upper half of the reflecting board 13 serves as a reflecting surface 15 for ascending stairs and a lower half serves as a reflecting surface 16 for descending stairs. Light from the light source 14 is reflected by the reflecting surface 15 toward a direction of angle A with respect to a perpendicular direction while reflected toward a direction of angle B by the reflecting surface 16. Thus both ascending stairs 17 and descending stairs 18 are equipped with light distribution over entire width of the light source 14. Therefore, even if the stairs 17 and the stairs 18 are located either right or left with respect to a landing 19, optimum light distribution can be obtained.