Optical disk and optical disk apparatus

An optical disc device for driving an optical disc, in which a plurality of concentric circular or spiral tracks are formed in a control track area where control data are recorded, in the vicinity of at least one selected from an inner circumferential end and a peripheral end, and in a rewritable area located outside the control track area for recording user data at least in one direction either from an inner circumference to a periphery or from the periphery to the inner circumference depending on the position of the control track area, and a plurality of segments are formed in each track, each segment including a clock area where a clock mark is arranged, a servo area where a pair of wobble marks displaced in both inner circumferential and peripheral directions from a center line of a track and separated by a predetermined distance in a circumferential direction, an address area where an address mark is arranged and a data area for recording the control data or the user data, wherein the clock mark, the wobble marks and the address mark are formed as prepits of an uneven shape, and, following the data area where the control data are recorded by the prepits of an uneven shape, a space of a predetermined length where the prepits do not exist is arranged for each segment in the control track area, the optical disc device comprising

• reproduction means for reproducing pit signals corresponding to the prepits,
• clock mark detection means for detecting a pit signal following a distance of not less than a distance corresponding to the space length from the pit signals reproduced by the reproduction means as the clock mark,
• servo clock generating means for generating a servo clock synchronized with the clock mark detected by the clock mark detection means, and
• control data readout means for reading out the control data based on the servo clock.