A method of setting a location of an imaging device includes (a) preparing a base unit, the base unit including a lens and a mounting boss; (b) mounting an imaging device, on which a reference point is formed, to a circuit board; (c) forming a mounting hole at a predetermined location of the circuit board based on the reference point of the imaging device; and (d) mounting the circuit board to the base unit by inserting the mounting boss into the mounting hole.