A filter capacitor 12 accumulating direct-current power and a semiconductor device module performing a switching operation that converts the direct-current power accumulated in the filter capacitor 12 to alternating-current power are electrically connected with each other through a laminated bus bar. The laminated bus bar has a first bus bar and a second bus bar 16b in which a plurality of connection conductors are laminated through an insulator. The second bus bar 16b is provided with heat radiating portions 22, 24 that are formed by exposing a part of the conductor in each flat plate surface.
