To suppress the reduction in reliability of a resin-sealed semiconductor device. A first cap (member) and a second cap (member) with a cavity (space formation portion) are superimposed and bonded together to form a sealed space. A semiconductor including a sensor chip (semiconductor chip) and wires inside the space is manufactured in the following way. In a sealing step of sealing a joint part between the caps, a sealing member is formed of resin such that an entirety of an upper surface of the second cap and an entirety of a lower surface of the first cap are respectively exposed. Thus, in the sealing step, the pressure acting in the direction of crushing the second cap can be decreased.