An acoustic wave element includes: a piezoelectric substrate; an IDT (Interdigital Transducer) formed on the piezoelectric substrate; and an end face of the piezoelectric substrate that is formed on at least one end of the IDT in a propagation direction of an acoustic wave; wherein when a wavelength of the acoustic wave which the IDT excites is expressed by “λ” and a metallization ratio of the IDT is expressed by “D”, a distance between an inner end of an electrode finger of the IDT nearest to the end face and the end face is equal to or more than 7λ/16+D×λ/4 and equal to or less than 3λ/4+D×λ/4.