The present invention is directed to improve reliability of a semiconductor device. A semiconductor device manufacturing method includes: (a) a step of attaching a BGA having a solder ball to a socket for a burn-in test; and (b) a step of performing a burn-in test of the BGA by sandwiching the solder ball by conductive contact pins in the socket. The contact pin in the socket has a first projection part which is conductive and extends along an attachment direction of the BGA and a second projection part which is conductive, provided along a direction crossing the extension direction of the first projection part, and placed so as to face the surface on the attachment side of the BGA of the solder ball. In the step (b), a burn-in test of the BGA is performed in a state where the first projection parts in the contact pins are in contact with the solder ball.