An electro-optical device cased in a mounting case includes an electro-optical device having an image display region on which projection light from a light source is incident, 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, the mounting case accommodating the electro-optical device by holding at least a portion of a peripheral region located at the circumference of the image display region of the electro-optical device with at least one of the plate and the cover. In addition, the cover includes a cooling air introducing portion, and the cooling air introducing portion having a cooling air guiding portion to allow the cooling air which is blown to the electro-optical device encased in the mounting case to flow toward the image display region.