To provide a display device of a lamp bulb for a vehicle by which both of direct light and reflected light can be observed.

This display device 1 of the lamp bulb for the vehicle is provided with a case 2 housing the lamp bulb 3 for the vehicle. On the case 2, a window part 4 for the direct light and a window part 5 for the reflected light for respectively guiding the light emitted from the lamp bulb 3 for the vehicle to the outside are formed. On the outside of the case 2, a reflector 6 for reflecting the light passed through the window part 5 for the reflected light is provided. Thus, the direct light passed through the window part 4 for the direct light and the reflected light passed through the window part 5 for the reflected light and reflected on the reflector 6 are observed.