A lens mounting plate to which a projection lens unit is fixed is brought into contact with a sliding base. The lens mounting plate is pressed against the sliding base by the urging of a coiled spring. The pressing force is set such that the position of the projection lens unit can be held and shifted. A cover is provided with a pipe-shaped projection so as to surround the projection lens unit with a clearance corresponding to the shifting width of the projection lens unit between the pipe-shaped projection and the projection lens unit. A user shifts the position of the projection lens unit with his or her fingers laid on the pipe-shaped projection and the projection lens unit.