A subject matter of this invention is that a manufacturing yield of a semiconductor device is improved.A resistance value between a pogo pin and a test pin is measured by bringing a plurality of pogo pins of a socket mounted over a test board included in an inspection device of a semiconductor device into contact with a plurality of solder balls, respectively, and bringing the test pin provided in the socket into contact with a first solder ball of a plurality of solder balls at a position different from a position where the pogo pin is brought into contact with the first solder ball. Thereby, a coupling failure between the pogo pin and the first solder ball is detected, so that a conductive state is inspected.