In a piezoelectric resonator manufacturing method, a sacrificial layer is formed on a back surface of a piezoelectric substrate. A support layer is formed on the back surface of the piezoelectric substrate so as to cover the sacrificial layer. A support layer as a piezoelectric resonator is formed by flattening the support layer. A recess in which the surface of the sacrificial layer is recessed with respect to the surface of the support layer is formed by abrading the surfaces of the support layer and the sacrificial layer. The recess extends to a vicinity of a boundary surface between the support layer and the sacrificial layer in the support layer. A support substrate is adhered to the surfaces of the support layer including the recess and the sacrificial layer via an adhesive material.