An electric drive system comprising a power control unit for converting direct-current power to alternating-current power and supplying the converted power to an electric motor for driving a vehicle, and an onboard device case inside which the power control unit is fixed, the power control unit comprising: a step-down converter configured to step down voltage of the direct-current power; and a step-up converter configured to step up voltage of the direct-current power, the step-up converter including a reactor and a capacitor , the reactor and the step-down converter being fixed to the onboard device case , and the reactor and the step-down converter being stacked, the capacitor being affixed to the onboard device case and arranged next to at least one of the reactor or the step-down converter , with respect to a direction in which the reactor and the step-down converter are stacked, and the capacitor and at least one of the step-down converter or the reactor being fixed together by a bus bar , the bus bar being configured to electrically connect a terminal of the capacitor to a terminal of at least one of the step-down converter or the reactor , wherein the capacitor is fixed to the onboard device case at fixing points in two locations; and the bus bar fixes the capacitor to at least one of the step-down converter or the reactor at a position away from a straight line that passes through the fixing points in two locations in a stacking direction. the power control unit being characterized in that the bus bar is a linear, flat plate-like conductor plate that extends in a direction that orthogonally intersects a direction in which the straight line that passes through the fixing points in two locations of the capacitor extends. a step-down converter configured to step down voltage of the direct-current power; and a step-up converter configured to step up voltage of the direct-current power, the step-up converter including a reactor and a capacitor , the reactor and the step-down converter being fixed to the onboard device case , and the reactor and the step-down converter being stacked, the capacitor being affixed to the onboard device case and arranged next to at least one of the reactor or the step-down converter , with respect to a direction in which the reactor and the step-down converter are stacked, and the capacitor and at least one of the step-down converter or the reactor being fixed together by a bus bar , the bus bar being configured to electrically connect a terminal of the capacitor to a terminal of at least one of the step-down converter or the reactor , wherein the capacitor is fixed to the onboard device case at fixing points in two locations; and the bus bar fixes the capacitor to at least one of the step-down converter or the reactor at a position away from a straight line that passes through the fixing points in two locations in a stacking direction. the power control unit being characterized in that the bus bar is a linear, flat plate-like conductor plate that extends in a direction that orthogonally intersects a direction in which the straight line that passes through the fixing points in two locations of the capacitor extends. <EOS>