To lessen a size of a filter structure required for a multi-system mobile communication means, by integrating a resonator element and a switch element on the same base and in the same process.

A bulk acoustic wave(BAW) resonator having an etch pit structure is formed by laminating a film layer 130, a bottom electrode 110, a piezoelectric layer 100 and a top electrode 120 on a base 120. In this etch pit structure, the etch pit 210 is formed under the BAW structure by etching after at least the film layer 130 is adhered. Or, a sacrificing layer is first adhered and patterned, before other layer of the BAW structure is adhered. A remaining part of the BAW structure is partially adhered on the sacrificing layer and patterned After the remaining part of the BAW structure is completed, the sacrificing layer is eliminated by etching. A metal or a polymer is used for a material for this sacrificing layer.