An acoustic wave device includes a plurality of acoustic wave devices each including a substrate made of a piezoelectric material, a pair of interdigital electrodes formed on the substrate, each of the interdigital electrodes including a plurality of electrode fingers, and an adjustment medium. The adjustment medium includes at least a single layer and is formed on at least a part of the pair of the interdigital electrodes. The adjustment medium further includes at least one thick portion and a thin portion, the thin portion being null or thinner than the thick portion, a total area of the at least one thick portion in a region covering the pair of interdigital electrodes being determined according to a predetermined characteristic value, wherein the plurality of acoustic wave devices include at least two acoustic wave devices that differ from each other with respect to the size of the total area of the at least one thick portion of the adjustment medium.