A surface acoustic wave filter device includes surface acoustic wave filters, one of which includes a longitudinally coupled resonator-type first filter section and a longitudinally coupled resonator-type second filter section. The second filter section is electrically connected in parallel or series with the first filter section on at least one of an input signal side and an output signal side. The first filter section includes a first IDT group including three IDTs. The second filter section includes a second IDT group including three IDTs. Another surface acoustic wave filter includes a third IDT group that is cascade connected to the first filter section and the second filter section and includes IDTs arranged in order in a line in a surface acoustic wave propagation direction.

In a filter device, first and second filter sections are connected in parallel between an input terminal and an output terminal. The first filter section is a longitudinally coupled resonator-type elastic wave filter including first and second inter-stage wiring lines with a two-stage cascading connection. The second filter section is a longitudinally coupled resonator-type elastic wave filter including third and fourth inter-stage wiring lines with a two-stage cascading connection. The phases of signals flowing in the third inter-stage wiring line and the second inter-stage wiring line are inverse. Terminal portions of an interdigital transducer electrode connected to the second inter-stage wiring line and an interdigital transducer electrode connected to the third inter-stage wiring line that are connected to a potential that is not a hot-side potential are connected by a virtual ground wiring line. A hot-side wiring portion that is adjacent to the virtual ground wiring line is disposed on an insulating film provided on the piezoelectric substrate.

Provided is a method for manufacturing a surface acoustic wave apparatus that can reduce degradation of electric characteristics and also reduce the number of manufacturing processes. The method for manufacturing a surface acoustic wave apparatus includes the steps of: forming an IDT electrode on an upper surface of a piezoelectric substrate, forming a frame member surrounding a formation area in which the IDT electrode is formed on the piezoelectric substrate, and mounting a film-shaped lid member on the upper surface of the frame member so as to be joined to the frame member so that a protective cover, used for covering the formation area and for providing a tightly-closed space between it and the formation area, is formed.

A surface acoustic wave filter includes a longitudinally coupled resonator first filter section and a longitudinally coupled resonator second filter section that is electrically connected to the first filter section in parallel or in series and that is provided next to the first filter section in a surface acoustic wave propagation direction. The first filter section includes a first interdigital transducer group arranged in the surface acoustic wave propagation direction. The second filter section includes a second interdigital transducer group arranged in the surface acoustic wave propagation direction. A reflector between the first interdigital transducer group and the second interdigital transducer group is an integrated shared reflector. A number of electrode fingers in reflecting units in the shared reflector is an odd number of no less than nine.