VIRTUAL IMAGE DISPLAY DEVICE

A virtual image display device includes: an image projection unit that selectively projects a first projection light linearly polarized in a first direction and a second projection light linearly polarized in a second direction orthogonal to the first direction to a windshield; a reflected light measurement unit that measures an intensity of light incident from the windshield into the image projection unit along a light path in which the first projection light and the second projection light are projected; and a determination unit that determine whether a user is wearing polarized sunglasses that shield a component linearly polarized in the first direction, based on a first light intensity measured by the reflected light measurement unit when the first projection light is projected and a second light intensity measured by the reflected light measurement unit when the second projection light is projected.