To improve insulation between filters and duplexer characteristics at block frequency regions by providing steps at both sides of a ground electrode pattern in the bottom of a recess for housing a surface wave element, settling input/output pads and grounding pads on the top thereof, and connecting the ground electrode pattern through a conductor pattern disposed along the steps side faces.

Surface wave elements 4 are disposed in a recess 3 on the top of a surface mount type ceramic package 2, a metal cover is fixed onto the recess 3 to close it, wire bonding input/output pads 11a, 11b, grounding pads 12, 12c, etc., are formed on two opposite facing 10 in the recess 3, a ground electrode pattern is formed on the inner bottom face of the recess 3, and electrode terminals 11a, 11b are connected to outer electrodes on the outer bottom face through conductors running in the ceramic package 2. The elastic surface wave element 4 comprises a plurality of electrode fingers 21 on a piezoelectric substrate 20, a plurality of input/output pads 11a, 11b on the steps 10 at the package, grounding pads 12, 12c and bonding pads 22.