An acoustic wave resonator that is excellent in terms of return loss characteristics at the resonant and anti-resonant frequencies and that is capable of effectively reducing loss includes an IDT electrode in which a plurality of first electrode fingers and a plurality of second dummy electrode fingers are connected to a first common electrode, a plurality of second electrode fingers and a plurality of first dummy electrode fingers are connected to a second common electrode. Apodization weighting is applied in the acoustic wave propagation direction. The metallization ratio of a non-crossing region is relatively high compared with the metallization ratio of a crossing region in the acoustic wave propagation direction.