A power module is obtained in which the thermal resistance in the range from a semiconductor device to a base plate is reduced and the stress in the joining portion is relieved. The power module includes at least one semiconductor device, an insulating substrate having an insulating layer, a circuit layer provided on an upper surface of the insulating layer and a metal layer provided on a lower surface of the insulating layer, and a sintering joining member with an upper surface larger in outer circumference than a back surface of the at least one semiconductor device, to join together the back surface of the at least one semiconductor device and an upper surface of the circuit layer on an upper-surface side of the insulating layer.