A method is provided for manufacturing a bonded wafer by an ion implantation delamination method, including bonding a base wafer with a bond wafer having a microbubble layer formed by ion implantation, delaminating the wafers along the micro bubble layer as a boundary, and removing a periphery of a thin film formed on the base wafer by the delamination. The removal step is performed by dry etching that supplies an etching gas from a nozzle, and the dry etching is performed by adjusting an inner diameter of the gas-jetting port of the nozzle, and a distance between the gas-jetting port of the nozzle and a surface of the thin film.