Thickness of a pressure-detecting piezoelectric substrate (2) that is thinner than that of a supporting piezoelectric substrate (3) and that has a surface acoustic wave element for pressure detection (7a) on its lower surface is mounted on the supporting piezoelectric substrate (3) having a surface acoustic wave element for reference (4a) on its upper surface. A sealing member (5) is provided between the supporting piezoelectric substrate (3) and the pressure-detecting piezoelectric substrate (1). The surface acoustic wave element for pressure detection (7a) and the surface acoustic wave element for reference (4a) can be disposed in a space (S) enclosed with the pressure-detecting piezoelectric substrate (1) and the sealing member (5). It is possible to provide a small-sized pressure sensor device (1) that can perform temperature compensation and that has high reliability.