A three-dimensional display device , comprising: a display panel including subpixels configured to display a parallax image including a first image and a second image having parallax between the images; a shutter panel configured to define a traveling direction of image light representing the parallax image from the display panel ; and a controller configured to change, in a certain time cycle, wherein the certain time cycle is a period for which continuous irradiation with sunlight is to be avoided in a specific part of the display panel , areas on the shutter panel in a light transmissive state to transmit the image light with at least a certain transmittance and areas on the shutter panel in a light attenuating state to transmit the image light with a transmittance lower than the transmittance in the light transmissive state, and to change the subpixels to display the first image and the second image based on positions of the areas in the light transmissive state, wherein the controller is configured to control first areas on the shutter panel into the light transmissive state during a first period included in the certain time cycle and the controller is configured to control areas on the shutter panel other than the first areas into the light attenuating state during the first period, wherein the controller is configured to control second areas on the shutter panel into the light transmissive state during a second period and the controller is configured to control areas on the shutter panel other than the second areas into the light attenuating state during the second period, and wherein the second areas are areas at least partially different from the first areas and the second areas include parts of the first areas . a display panel including subpixels configured to display a parallax image including a first image and a second image having parallax between the images; a shutter panel configured to define a traveling direction of image light representing the parallax image from the display panel ; and a controller configured to change, in a certain time cycle, wherein the certain time cycle is a period for which continuous irradiation with sunlight is to be avoided in a specific part of the display panel , areas on the shutter panel in a light transmissive state to transmit the image light with at least a certain transmittance and areas on the shutter panel in a light attenuating state to transmit the image light with a transmittance lower than the transmittance in the light transmissive state, and to change the subpixels to display the first image and the second image based on positions of the areas in the light transmissive state, wherein the controller is configured to control first areas on the shutter panel into the light transmissive state during a first period included in the certain time cycle and the controller is configured to control areas on the shutter panel other than the first areas into the light attenuating state during the first period, wherein the controller is configured to control second areas on the shutter panel into the light transmissive state during a second period and the controller is configured to control areas on the shutter panel other than the second areas into the light attenuating state during the second period, and wherein the second areas are areas at least partially different from the first areas and the second areas include parts of the first areas . <EOS>