A semiconductor device includes a semiconductor element having first and second main surfaces spaced apart in a thickness direction. The semiconductor element includes a metal underlying layer on the first main surface, a bonding pad on the metal underlying layer with a wire bonded to the pad, and an insulative protection layer formed on the first main surface and surrounding the bonding pad. The bonding pad includes first and second conductive layers. The first conductive layer covers the metal underlying layer and is made of a metal having a lower ionization tendency than the metal underlying layer. The second conductive layer covers the first conductive layer and is made of a metal having a lower ionization tendency than the first conductive layer. The first and second conductive layers have respective peripheries held in close contact with the protection layer and covering a part of the protection layer.