An optical pickup device including: a light source for emitting a light beam; a beam expander having a converging lens for converging a light beam, a light-shielding panel having a through-portion arranged at an optical conjugate position of an emission point of the light beam for allowing the converged light beam to pass through and a collimator lens for collimating the light beam passed through the through-portion; an objective lens for focusing the collimated light beam to the recording layer; and a light detector for detecting the light beam reflected by the recording medium and passed through the objective lens and the beam expander and generating the error signal and the reading data signal for controlling the focusing position.