PURPOSE: To facilitate high speed movement of an optical pickup and to attain high speed access by radiating a laser light from an optical pickup section to a recording and reproducing face of an information recording medium driven via a galvano mirror and driving the galvano mirror in the radial direction.

CONSTITUTION: A laser beam 33 coming from an optical pickup 40 is projected onto a point S on a rotary shaft of a galvano mirror 31, the laser beam 33 is reflected and focused onto a recording and reproducing face of a driven disk 32 curved as a recess. Moreover, the galvano mirror 31 is driven to scan the focused laser beam 33 in the radial direction of the recording and reproducing face. Since the recording and reproducing face of the disk 32 is curved so that a distance R between the recording and reproducing face and the center point S of the galvano mirror 31 is equal to each other independently of the position of the recording and reproducing face, the laser beam 33 on the recording and reproducing face is scanned without out of focus even when the rotary angle is changed. Thus, the entire recording and reproducing face of the information recording disk medium is scanned and high speed access is facilitated.