PURPOSE: To obtain the head mount display device in which an electronic video image not affected by an external light is displayed onto an optional location of an external field image with a small size, light weight and providing an excellent mount sense.

CONSTITUTION: The head mount type display device observing an electronic video image displayed on a picture display element D1 is provided with a half mirror M1 arranged in front of a pupil of an eye and overlapping an external field image and the electronic video image and with a transparent liquid crystal display panel E1 being able to shield the light of an optional area in the luminous flux of the external field image O and a shield area (h) is changed attended with a change in the display position of the electronic video image.