A magneto-caloric-effect element has a plurality of element units. The element units have lengths, respectively. The element units have different Curie temperatures, respectively. The element units demonstrate magneto-caloric effects. Two adjoining performance distribution crosses at a cross temperature. A temperature in the rated operational status between two adjoining element units is called a boundary temperature. The lengths and/or Curie temperatures are set so that the boundary temperatures and the cross temperatures coincide each other. Thereby, a plurality of element units can function at high effectiveness in the rated operational status.