A projection optical apparatus includes an optical system and a projection optic enclosure that accommodates the optical system. The optical system includes a first optical system on which the image light is incident, and the projection optic enclosure includes a first accommodation section that accommodates the first optical system and includes a flange section (supported section) supported by the image forming apparatus and a first wall section and a second wall section that face each other in a first direction (Y direction) that intersects the direction along a line that connects the flange section to the center of gravity of the projection optical apparatus.