A power conversion device includes a power conversion module, a phase change material, a heat dissipation member, a cooling mechanism, and a controller. A semiconductor switching element and a freewheeling diode configure a power conversion circuit. The phase change material is provided on a principal plane of a casing. The heat dissipation member includes a heat dissipation surface. The heat dissipation surface is overlapped with the principal plane to sandwich the phase change material. The cooling mechanism cools the heat dissipation member. The controller generates a driving signal for driving the power conversion circuit and controls the cooling mechanism. The controller includes a predetermined heating operation. The heating operation may drive the power conversion circuit, in a state that the cooling mechanism is stopped or intermittently operated, such that heat generation occurs in both the semiconductor switching element and the freewheeling diode.