A head mounted display device includes: a display module displaying an image; a calculator including an adaptive luminance calculator that scans a first image based on a predetermined viewing angle and calculates a first adaptive luminance of the first image, and a discomfort luminance calculator that calculates a first discomfort luminance based on the first adaptive luminance according to an equation that models a relationship between the first adaptive luminance and the first discomfort luminance at which a user perceives discomfort; and a luminance controller that controls a dimming level of the display module to be equal to or less than the first discomfort luminance.