A semiconductor processing apparatus according to the present embodiment is provided with a stage capable of placing a semiconductor substrate thereon and of rotating the semiconductor substrate. A plurality of holders are provided on the stage, to hold an edge of the semiconductor substrate. A plurality of sensors are provided to the plurality of holders, respectively, to detect the edge of the semiconductor substrate. An elevator mechanism is capable of changing heights of the holders. A controller controls the elevator mechanism to change the heights of the holders so that the plurality of sensors detect the edge of the semiconductor substrate.