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.