To provide an information recording medium in which both satisfactory reproduction information from pit trains for reproduction only and satisfactory reproduction information from a guide groove for recording and reproducing can be obtained and the optimum tracking property can be obtained always even in an unrecorded region and the optimum tracking property can be obtained always even in an already recorded region, by reproducing an intermediate region consisting of the pit arrays with the tracking system of a differential push-pull system or a phase differential system.

The information recording medium is provided, in which bottom positions of the guide grooves and the pit arrays formed on the disk substrate are both flat on one and the same plane, and intermediate regions consisting of the pit array where the height varies between the height from the bottom surface to the side surfaces of the guide grooves and the height from the bottom surface to the side surfaces of the pit array are prepared at a switching part where switching is varied from the pit array to the guide grooves or from the guide grooves to the pit array.

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