A method for manufacturing a surface acoustic wave filter device includes
a step of forming grooves in one principal surface of a piezoelectric
substrate, a step of embedding a metallic film in the grooves to form IDT
electrodes, a step of performing a process of removing a portion of the
piezoelectric substrate from the one principal surface of the
piezoelectric substrate, thereby forming a recessed portion including the
bottom surface in which the IDT electrodes are embedded, and a step of
bonding a cover member to the piezoelectric substrate.