PURPOSE: To obtain the indicator lamp apparatus which is so well designed that a display is suspended in the air by providing a surface type transparent photoconductor which receives light from one or plural light sources and a light diffuse reflecting part which diffuses and reflects the light of the light sources passed through the transparent photoconductor.

CONSTITUTION: The photoconductor 21 is fixed to a lamp house so that its end surface 11 is parallel to a fluorescent lamp 9. The extension part 21a of this photoconductor 21, the light diffuse reflecting part 12, and a display plate 13 constitute a display body 14. The light diffuse reflection part 12 on which white ink, etc., is printed occupies the extension part 21a of the photoconductor more and more with the distance from the fluorescent lamp 9. Namely, the display plate 13 is uniformly brightened by making the quantity of light reflection larger and larger with the distance from the fluorescent lamp 13. At the part of the photoconductor 21, emitted luminous flux from the fluorescent lamp 9 travels while reflected nearly totally on the border surface of air, so the light never leaks out of the photoconductor 21. Then the photoconductor 21 is transparent, so it seems that only the display part is suspended in the air.