Image projection apparatus having a dust-proof enclosure portion, a cabinet shielding structure and a detachably dust-proof cover

A dust-proof enclosure portion which stores therein an emission portion of a projection unit and in which a projection window from which image light is emitted is formed to direct upward, and a cabinet shielding structure which holds a screen on a front side, in which an opening that introduces the image light emitted from the projection window of the projection unit is included, and in which a second reflection mirror that reflects the introduced image light toward the rear surface of the screen is arranged are included, in which a second dust-proof cover is detachably attached to the opening (light introducing and managing opening) of the cabinet shielding structure, the projection window is exposed in a state where the second dust-proof cover is removed, and the cabinet shielding structure is a sealed structure in a state where the second dust-proof cover is attached.