A spin wave element includes a substrate, a multilayer, a detecting portion, and two or more input portions. The multilayer having a lamination direction thereof is formed on the substrate and includes a first ferromagnetic layer. The first ferromagnetic layer has magnetization whose direction is in the lamination direction. The detecting portion and the input portions are formed on the multilayer and separated from each other by a first nonmagnetic layer. In addition, a portion of an outer edge of the multilayer viewed from the lamination direction makes a portion of one ellipsoid. The detecting portion and one of the input portions are located on the long axis of the one ellipsoid. The portion of the one ellipsoid is located on a side of one of the input portions.