Reliability of a semiconductor device is improved.A wire bonding step includes a step of exposing a wire and a pad electrode to a reducing gas atmosphere, forming a first hydroxyl layer on a surface of a ball portion, and forming a second hydroxyl layer on a surface of the pad electrode, a first bonding step of temporarily joining the ball portion to the pad electrode through the first hydroxyl layer and the second hydroxyl layer, and after the first bonding step, a step of actually joining the ball portion to the pad electrode by performing a heat treatment on a semiconductor chip and a base material.