A filter device includes a first input/output terminal and a second input/output terminal, as well as a series-arm circuit disposed on a path that connects the first input/output terminal and the second input/output terminal, and a parallel-arm circuit connected to a node on the path and a ground. At least one of the series-arm circuit or the parallel-arm circuit includes a resonance circuit, and the resonance circuit includes a first acoustic wave resonator, and a first capacitor connected in parallel to the first acoustic wave resonator, and having a greater electrostatic capacitance per unit area than that for the first acoustic wave resonator.