To make it possible to easily mold a substrate having high flatness by forming a molding surface to a shape to correct variations in the thickness of the substrate occurring in a difference in a shrinkage rate when a substrate material cures.

Both sides of the molding surface of a stationary side metal mold and the molding surface 3a of a moving side metal mold 3 or either of the molding surface of the stationary side metal mold and the molding surface 3a of the moving side metal mold 3 is formed to the shape to correct variations in the thickness of the disk substrate formed by curing of the resin material packed into a cavity. Namely, as shown in the molding surface 3a of the moving side metal mold 3, the molding surface is so formed that the region between the outermost peripheral portion and the innermost peripheral portion is more recessed than the innermost peripheral portion which is adjacent to the outermost peripheral part molding the outermost peripheral part of the disk substrate and a through-hole 3b and molds molding the innermost peripheral part of the disk substrate. The stationary side metal mold is formed to the shape similar to the shape of the moving side metal mold 3 in the case of the correction of the variations in the thickness of the disk substrate occurring in the difference in the shrinkage rate of the resin material even on the stationary side metal mold side.