A surface acoustic wave device includes a piezoelectric substrate, an interdigital transducer electrode that is disposed on a main surface of the piezoelectric substrate, a plurality of partition-support layers each of which is arranged in a region of the main surface surrounded by an outer periphery of the main surface, and a cover layer that is disposed above the plurality of partition-support layers and that covers the interdigital transducer electrode. The plurality of partition-support layers include a first partition-support layer and a second partition-support layer that are adjacent to each other, and a portion of the first partition-support layer and a portion of the second partition-support layer do not overlap each other when viewed from a second direction perpendicular or substantially perpendicular to a first direction in which the plurality of partition-support layers extend.