A method for manufacturing a semiconductor device is provided including: providing a reinforcing member on one surface of a wiring substrate that has a first region where a semiconductor chip is mounted and a second region around the first region, and has terminals extending from the first region to the second region formed on another surface thereof, in a manner that the reinforcing member overlaps the terminals and a part thereof protrudes from the first region to the second region; punching through from a surface side having the terminals in the wiring substrate, thereby cutting the terminals along a boundary between the first region and the second region; and punching through from the surface side having the reinforcing member in the wiring substrate, thereby continuously cutting the reinforcing member from an inboard side thereof to an outboard side along the boundary between the first region and the second region.