According to an aspect of the present disclosure, a semiconductor manufacturing apparatus includes a stage having a mounting region for a wafer on an upper surface, a plurality of sucking pipes extending from the mounting region to a back surface side of the stage through the stage, a vacuum pump that is connected to the plurality of sucking pipes and sucks the wafer onto the mounting region via the plurality of sucking pipes, a cup provided on the upper surface of the stage and covering the wafer, a gas supply line that pressurizes a space surrounded by the upper surface of the stage and the cup and a pressure sensor that detects pressure in the plurality of sucking pipes.