A method of manufacturing a semiconductor device flip-chip bonds electrode terminals of a substrate and a semiconductor chip together by solid-phase diffusion and underfills a gap between the substrate and the semiconductor chip with a thermosetting resin without the bonds between the terminals breaking due to heat in an underfill hardening step. The method includes a bonding step of flip-chip bonding the electrode terminals of the substrate and the semiconductor chip by solid-phase diffusion, an underfill filling step of filling the gap between the substrate and the semiconductor chip with the underfill material, and the underfill hardening step where the underfill material is heated to the hardening temperature to harden the underfill material. During the underfill hardening step, a member with a lower coefficient of thermal expansion out of the substrate and the semiconductor chip is heated to a higher temperature than the other member.