Abstract: Regarding optical pickup devices usable for performing recording on and reproduction from a plurality of types of optical discs, there is a problem that because of the structure of locating many optical elements in a height direction of an optical system, the height of the optical system is increased and so it is difficult to realize a thin and compact optical pickup device. According to the present invention, a first wave plate is located between a first light source and a first mirror, a second wave plate is located between a second light source and a second mirror, and the first wave plate and the second wave plate cause a desirable phase shift to light beams of the first through third wavelengths. Owing to this, the number of optical elements located in the height direction of the optical system can be decreased, and so the height of the optical system can be reduced.