In a head-mounted display device, image display light emitted from a display device is directed towards the eye of an observer by changing the light path thereof by means of an optical system. The display device, optical system and a drive signal generating device for the display device are worn on the head of the observer by means of a holding member. This optical system is positioned in front of the display device emitting display light in a forward direction from a position separated radially from the visual axis of the observer when looking straight ahead. The drive signal generating device is located in a position separated radially from the visual axis with an interval from the display device and optical system.