A power inverter includes a power semiconductor module that includes a power semiconductor device, a control circuit board that outputs a control signal used for controlling the power semiconductor device, a driver circuit board that outputs a driving signal used for driving the power semiconductor device, a conductive metal base plate arranged in a space between the driver circuit board and the control circuit board in which a fine and long opening portion is formed, wiring that connects the driver circuit board and the control circuit board through the opening portion and delivers the control signal to the driver circuit board, and an AC busbar that is arranged on a side opposite to the metal base plate through the driver circuit board and delivers an AC current output from the power semiconductor module to a drive motor. At least a portion of the AC busbar that faces the opening portion extends in a direction directly running in a longitudinal direction of the fine and long opening portion.