To provide a reflection type spherical aberration correction element which is easily downsized and easy in assembling and position adjustment as a means for correcting a spherical aberration caused in movement between layers in an optical pickup for performing the recording and reproducing of a multi-layer disk.

The reflection type spherical aberration correction element 40 having a reflection plane deformed in an uneven shape is arranged on an optical path as the means for correcting the spherical aberration. The reflection type spherical aberration correction element 40 includes a buckling type micro-actuator in which vibration plates (diaphragm) having such structure that a piezo thin film 44 is held between electrode films 43 and 45 are laminated on a semiconductor substrate 41, curvature of the reflection plane by the vibration plate is changed by controlling applied voltage to each electrode film 43, 45.