Acoustic wave filter device and multiplexer using same

An acoustic wave filter device comprising:

• a first terminal;
• a second terminal;
• a longitudinally coupled resonator coupled between the first terminal and the second terminal;
• and
• an inductor connected between a path and a ground potential, the path connecting the first terminal and the longitudinally coupled resonator to each other;
• wherein
• the longitudinally coupled resonator includes:
• at least one first IDT electrode coupled to the first terminal;
• and
• at least one second IDT electrode connected to the second terminal;
• a total area of an intersecting region of electrode fingers of the at least one first IDT electrode is smaller than a total area of an intersecting region of electrode fingers of the at least one second IDT electrode;
• each IDT electrode of the at least one first IDT electrode includes a first region in which electrode fingers are provided with a first pitch therebetween and a second region in which electrode fingers are provided with a second pitch therebetween, which is shorter than the first pitch;
• each IDT electrode of the at least one second IDT electrode includes a third region in which electrode fingers are provided with a third pitch therebetween and a fourth region in which electrode fingers are provided with a fourth pitch therebetween, which is shorter than the third pitch;
• the second region faces the fourth region;
• and
• a number of electrode fingers adjacent to each other with the second pitch therebetween in the second region is smaller than a number of electrode fingers adjacent to each other with the fourth pitch therebetween in the fourth region.