A projection-type image display device includes a first housing and a second housing. The first housing houses a light source unit configured to emit light, an image generating unit configured to modulate the light from the light source unit according to a video input signal to generate image light, and a projecting unit configured to project the image light generated by the image generating unit. The second housing includes an output unit configured to output a light signal and/or an input unit configured to input a light signal which are/is exposed and arranged on a surface of the second housing.