Semiconductor device

A semiconductor device includes: a semiconductor chip including a field effect transistor for switching; a die pad on which the semiconductor chip is mounted via a first bonding material; a lead electrically connected to a pad for source of the semiconductor chip through a metal plate; a lead coupling portion formed integrally with the lead; and a sealing portion for sealing them. A back surface electrode for drain of the semiconductor chip and the die pad are bonded via the first bonding material, the metal plate and the pad for source of the semiconductor chip are bonded via a second bonding material, and the metal plate and the lead coupling portion are bonded via a third bonding material. The first, second, and third bonding materials have conductivity, and an elastic modulus of each of the first and second bonding materials is lower than that of the third bonding material.