Abstract: A thermomagnetic cycle device includes a magnetocaloric effect element disposed between a high temperature end and a low temperature end, and a medium that that performs heat exchange with the magnetocaloric effect element. A magnetic field modulator periodically modulates an intensity of an external magnetic field so as to alternately repeat a magnetization period, during which the external magnetic field is applied to the magnetocaloric effect element, and a demagnetization period, during which the external magnetic field is annihilated. A heat transport device creates a relative movement between the magnetocaloric effect element and the medium. At least one of the magnetic field modulator and the heat transport device is configured such that a first heat exchange amount of the heat exchange during the magnetization period is different from a second heat exchange amount of the heat exchange during the demagnetization period.