OPTICAL STORAGE DEVICE

PURPOSE:To increase the storage capacity of a disk type recording medium by forming the scanning track line of a laser beam with which the concentric or spiral track of the recording medium is irradiated from an optical head slantingly to the radial axis of the recording medium. CONSTITUTION:The laser beam irradiated from the optical head 4 forms the scanning track line 10 which slants at an angle theta to the radial axis alpha of the recording medium 2. Therefore, the track pitch of the concentric or spiral track 11 formed on the recording surface 1 is so formed that the track pitch ti on the scanning track line 10 is longer than the track pitch tr on the radius axis alpha as actual track pitch. Consequently, the track pitch ti can be equalized to the conventional track pitch tr and the storage capacity of the recording medium 2 is increased.