A semiconductor device including: a semiconductor layer; an electrode pad provided above the semiconductor layer; an insulating layer provided above the electrode pad and having an opening which exposes at least part of the electrode pad; and a metal electrode provided at least in the opening and including a first portion provided above the electrode pad, and a second portion provided above part of the insulating layer positioned outside the electrode pad, an area of a top surface of the second portion being larger than an area of a top surface of the first portion.