ACOUSTIC WAVE FILTER DEVICE, COMPOSITE FILTER DEVICE AND MULTIPLEXER

The present invention provides an acoustic wave filter device which is capable of improving the attenuation characteristics in a specific frequency band in an attenuation band outside the passband. Anacoustic wave filter device (1) according to the present invention is configured such that: a longitudinally coupled resonator type acoustic wave filter (11) is arranged in a series arm that connectsan input terminal (2) and an output terminal (3) to each other; first and second parallel arm resonators (P1, P2) are respectively arranged in first and second parallel arms that connect the series arm and the ground potential to each other; an input-side ground terminal (15) of the longitudinally coupled resonator type acoustic wave filter (11) is commonly connected to the ground terminal of atleast one of the first and second parallel arm resonators (P1, P2); an output-side ground terminal 16 of the longitudinally coupled resonator type acoustic wave filter (11) is commonly connected to the ground terminal of at lea