An elastic wave device includes a piezoelectric substrate that includes first and second main surfaces which face each other, an interdigital transducer electrode that is provided on the first main surface of the piezoelectric substrate and includes a first electrode layer containing molybdenum as a main component, and a dielectric film that is provided on the piezoelectric substrate and covers the interdigital transducer electrode. The piezoelectric substrate is made of lithium niobate. The dielectric film is made of silicon oxide. The elastic wave device utilizes Rayleigh waves propagating through the piezoelectric substrate. The duty ratio of the interdigital transducer electrode is equal to or more than about 0.55 and less than or equal to about 0.75.