A head mounted display device includes a lens assembly which changes a path of light; a main display module which outputs a main image and is positioned in front of the lens assembly; a main optical block which shields at least a portion of a light representing the main image such that the light representing the main image faces the lens assembly; a sub-display module disposed on a side of the main optical block and which outputs a sub-image; a sub-optical block positioned on the side of the main optical block and which shields at least a portion of a light representing the sub-image; and a light path converter positioned in the sub-optical block and which changes a path of the light representing the sub-image such that the light representing the sub-image faces the lens assembly.