We propose a dual-plate pressure sensor operating with pressure-induced frequency shifts of thickness-shear modes of a crystal plate resonator. Under an applied normal pressure. The dual-plate structure causes flexure in the crystal plate rather than circumferential compression in usual thickness-shear pressure sensors. This suggests higher sensitivity because a plate responds to a normal pressure more than to a circumferential compression, which is shown by a theoretical analysis using the theory for small fields superposed on initial fields.