A three-dimensional display device includes a display panel, a barrier panel, and a controller that controls the display panel and the barrier panel. The controller defines multiple first image areas and multiple second image areas in the display panel, causes the first image areas to be at first intervals in a first direction, causes displaying of a first image viewable by a first eye of a user in the first image areas and a second image viewable by a second eye of the user in the second image areas, defines, in the barrier panel, multiple first transmissive areas transmissive to the image light at a first transmissivity and multiple second transmissive areas transmissive to the image light at a second transmissivity, causes the first transmissive areas to be at second intervals in the first direction, and performs an irregular process at third intervals in the first direction.