An image projection apparatus including a light source, a projection unit to project light from the light source, a dust-proof member to protect the projection unit from outside dust and through which light from the light source passes, a light detector provided at an end surface of the dust-proof member to detect reflected light of light projected from the projection unit, the reflected light being internally reflected light trapped within the dust-proof member, and a controller that executes a protective action when the amount of internally reflected light detected by the light detector meets or exceeds a predetermined threshold value.