To provide a mold which molds a molding substrate for an optical disk, suppresses the occurrence of burrs etc., adversely affecting the optical disk, and improves the thickness precision of the optical disk constituted of the molding substrate, the substrate for the optical disk improved in thickness precision, and the optical disk improved in thickness precision.

In the mold, a cavity for molding the molding substrate for the optical disk is formed, a stamper 23 for transferring a fine structure to the molding substrate is set to make the vicinity of the innermost peripheral part of the stamper 23 convex toward the cavity, and a surface formed by a mold member constituting the interior peripheral part 31 of the molding substrate 30 and an information area surface 33 to which the fine structure is transferred are approximately equal in height.