A semiconductor manufacturing device including a polishing head that is capable of retaining a semiconductor substrate; a polishing pad having a processing surface to be abutted to the semiconductor substrate retained by the polishing head, the processing surface including a groove; a platen that is capable of rotating about a rotary shaft running along a direction intersecting the processing surface, in a state in which the polishing pad is retained by the platen; a measuring section that outputs a measurement value indicating a height of the processing surface at a predetermined location along a circumference of a circle centered about the rotary shaft of the platen; and a derivation section that derives a depth of the groove from the measurement value of the measuring section.