A second wiring layer 362 of a multilayer wiring board constituting a power converter is provided with a first positive side direct current wiring 311p and a second positive side direct current wiring 312p constituting a direct current bus 300p. The first positive side direct current wiring 311p and the second positive side direct current wiring 312p as well as a negative side direct current wiring are provided with a bent structure for making a transmission path length on one side in a direct current transmitting direction shorter than a transmission path length on other side thereof. Line widths of the first positive side direct current wiring 311p and the second positive side direct current wiring 312p are set to a width equal to or larger than a width by which a damping factor of a noise current in the direct current transmitting direction becomes substantially a constant value.