A manufacturing method of semiconductor device capable of suppressing or preventing formation of a dissolution region of composition atoms such as a pit in a semiconductor wafer. After oxide film on a semiconductor wafer is removed by dipping plural pieces of the semiconductor wafer accommodated in a carrier into chemical liquid containing fluoro acid, chemical liquid adhering to the semiconductor wafer is washed out of the semiconductor wafer by rinse processing using de-ionized water. At least in the rinse processing of this wet processing, light is projected to the semiconductor wafer from a light source provided on a wet etching apparatus. Adjusting electromotive force caused by battery reaction at a pn junction of the semiconductor wafer by adjusting the state of the light L enables generation of a pit in the semiconductor wafer.