Acoustic wave filter device and multiplexer

An acoustic wave filter device comprising:

• a parallel arm resonator connected between a ground and a transmission path of a high-frequency signal, which connects a first terminal and a second terminal to or from which the high-frequency signal is input or output;
• a first longitudinally coupled resonance device including a plurality of first acoustic wave resonators disposed side by side in a propagation direction of acoustic waves and provided on the transmission path;
• and
• a second longitudinally coupled resonance device including a plurality of second acoustic wave resonators disposed side by side in the propagation direction of the acoustic waves and cascade-connected to the first longitudinally coupled resonance device;
• wherein
• each of the plurality of first acoustic wave resonators and each of the plurality of second acoustic wave resonators includes a first end connected to the ground;
• the parallel arm resonator, the first longitudinally coupled resonance device, and the second longitudinally coupled resonance device are provided on one substrate having piezoelectricity;
• and
• all of the grounds on the substrate, including the ground to which the parallel arm resonator is connected, the ground to which each of the plurality of first acoustic wave resonators is connected, and the ground to which each of the plurality of second acoustic wave resonators is connected, are commonly connected to one ground terminal on the substrate.