PURPOSE: To simplify a device by using a hologram which uses a focusing luminous flux generating means and a tracking luminous flux generating means in common.

CONSTITUTION: Pieces 72 and 71 of luminous flux for tracking are made incident on planes almost perpendicular to a plane formed of reference luminous flux 70 for generating pieces of luminous flux for focus adjustment and video signal reading and luminous flux 73 for focus adjustment at angles ± to the planes, thereby generating a hologram 74. This is reproduced to obtain signal readout luminous flux, luminous flux 76 for focus adjustment, and pieces 77 and 78 of luminous flux for tracking. The pieces 77 and 78 of luminous flux are converted on both sides of a video signal track of a video disk 49 and their reflected light beams are detected by detecting element 81 and 82 for tracking to drive an optical system so that the signal reading luminous flux does not deviates from the track. The luminous flux 73, on the other hand, is reflected by the disk 49 and passes through a half-mirror 44 to strike on an element 50 for focus detection. Thus, the hologram is used, so the device, becomes extremely simple. Further, the hologram can be copied, so it is inexpensive.