Provided is an electro-optical device encased in a mounting case including an electro-optical device having a substrate in which projection light from a light source is incident on an image display region, and a mounting case including a plate disposed to face one surface of the electro-optical device and a cover to cover the electro-optical device, a portion of the cover abutting against the plate, and the mounting case accommodating the electro-optical device by holding at least a portion of the peripheral region positioned at the periphery of the image display region of the electro-optical device with at least one of the plate and the cover. Also, the plate has a coefficient of linear expansion within a predetermined range on the basis of the coefficient of linear expansion of the substrate.