The present invention provides an optical pickup device and a disc device. In the recording reproduction of the multi-layer discs, a focus error signal and a tracking error signal are not affected by stray light from other layers, thereby obtaining stable servo signals. The reflection light reflected from the optical multi-layer disc is divided into a plurality of regions, the divided optical beams are focused onto different positions on a photodetector, and a focus error signal is detected by employing a plurality of the divided optical beams by utilizing the knife edge method, and further,a tracking error signal is detected by employing a plurality of the divided optical beams. Furthermore, the dividing regions of the optical beam and light receiving parts are arranged in such a manner that stray light derived from other layers of the optical disc is not entered to a servo signal-purpose light receiving part of the photodetector when the divided optical beam is focused onto a target layer of the optical disc.