A magnetic heat pump (100,101,102) comprising: at least one magnetocaloric member (1,11) made of a magnetocaloric material; an impeller having a center axis and at least one accommodation chamber aligned in a circumferential direction with respect to the center axis and accommodating the at least one magnetocaloric member (1,11); at least one deformable member (3,13) facing the at least one accommodation chamber and having a shape individually changing; a casing (4,14) having an interior space accommodating the at least one magnetocaloric member (1,11), the impeller, and the at least one deformable member (3,13) and allowing a heat transport medium to circulate, a first inlet for the heat transport medium to flow into the interior space, and a first outlet spaced apart from the first inlet in the circumferential direction and for the heat transport medium to flow out of the interior space; an electric motor to integrally rotate the impeller, the at least one magnetocaloric member (1,11), and the at least one deformable member (3,13) in a first direction from the first inlet toward the first outlet in the circumferential direction; and a magnetic field generator to produce a magnetic field becoming stronger along the first direction, in a first region extending from the first inlet to the first outlet in the first direction in the interior space, wherein the at least one accommodation chamber is open toward an outside in a radial direction with respect to the center axis, the shape of the at least one deformable member (3,13) individually changes with the rotation, the at least one accommodation chamber has a volume individually increasing and decreasing with the change of the shape of the at least one deformable member (3,13), and the volume when the at least one accommodation chamber is located in the first region is larger than the volume when the at least one accommodation chamber is located in a second region located backward of the first inlet in the first direction and the volume when the at least one accommodation chamber is located in a third region located forward of the first outlet in the first direction. at least one magnetocaloric member (1,11) made of a magnetocaloric material; an impeller having a center axis and at least one accommodation chamber aligned in a circumferential direction with respect to the center axis and accommodating the at least one magnetocaloric member (1,11); at least one deformable member (3,13) facing the at least one accommodation chamber and having a shape individually changing; a casing (4,14) having an interior space accommodating the at least one magnetocaloric member (1,11), the impeller, and the at least one deformable member (3,13) and allowing a heat transport medium to circulate, a first inlet for the heat transport medium to flow into the interior space, and a first outlet spaced apart from the first inlet in the circumferential direction and for the heat transport medium to flow out of the interior space; an electric motor to integrally rotate the impeller, the at least one magnetocaloric member (1,11), and the at least one deformable member (3,13) in a first direction from the first inlet toward the first outlet in the circumferential direction; and a magnetic field generator to produce a magnetic field becoming stronger along the first direction, in a first region extending from the first inlet to the first outlet in the first direction in the interior space, wherein the at least one accommodation chamber is open toward an outside in a radial direction with respect to the center axis, the shape of the at least one deformable member (3,13) individually changes with the rotation, the at least one accommodation chamber has a volume individually increasing and decreasing with the change of the shape of the at least one deformable member (3,13), and the volume when the at least one accommodation chamber is located in the first region is larger than the volume when the at least one accommodation chamber is located in a second region located backward of the first inlet in the first direction and the volume when the at least one accommodation chamber is located in a third region located forward of the first outlet in the first direction.