A magnetic heat pump cycle has a first to a fourth steps, which are repeatedly carried out. In the first step, a movement of heat medium is stopped by a pressure valve and a pressure accumulating tank and a magnetic field is applied by a magnetic-field control unit to a magnetic working material. In the second step, the pressure valve is opened so that the heat medium flows in a working chamber from a second axial end to a first axial end, and the magnetic field is increased depending on a moving speed of the heat medium. In the third step, the movement of the heat medium is stopped and the magnetic field is decreased. In the fourth step, the heat medium is moved in a reversed direction and the magnetic field is decreased depending on the moving speed of the heat medium.