ELASTIC WAVE RESONATOR, ELASTIC WAVE FILTER, DEMULTIPLEXER, AND COMMUNICATION APPARATUS

The strength of a spurious signal is reduced while maintaining the uniformity of a resonant frequency in an identical elastic wave resonator. An elastic wave resonator (4) includes a piezoelectric body (6), and a plurality of electrode fingers (14, 22) located on the piezoelectric body and arranged in a propagation direction (TD) of an elastic wave. A region in which the plurality of electrode fingers are located includes a first region (24A) and a second region (24B) in a plan view. The plurality of electrode fingers include a first electrode finger group (14A) located in the first region and a second electrode finger group (14B) located in the second region, and a pitch (PA) of the first electrode finger group is different from a pitch (PB) of the second electrode finger group. The first region and the second region have frequency effective-characteristics acting in a direction to cancel out effects on a higher resonant or antiresonant frequency and a lower resonant or antiresonant frequency brought about by a magnitude correlation between the pitches of the first and second electrode finger groups.