To provide a method for manufacturing a master disk for an optical recording medium capable of efficiently manufacturing the master disk for the optical recording medium of a high recording density with high reliability.

The master disk for the optical recording medium is manufacturing by exposing and developing a photoresist 11 on a substrate 11 to form rugged patterns 12 and 13, regulating the photoresist 11 to a glass transition point or above by performing post baking and detecting the reflected and diffracted light obtained by irradiating the rugged patterns 13 of the photoresist 11 with the laser beam in the post baking process step. The master disk for the optical recording medium is manufactured by exposing and developing the photoresist on the substrate to form the first rugged patterns, subjecting the substrate to dry etching using the photoresist as a mask to form the second rugged patterns, removing the photoresist remaining on the substrate and detecting the reflected and diffracted light obtained by irradiating the second rugged patterns of the substrate with the laser beam in the dry etching process step.