A power converter in which the thermal influence of the semiconductor modules (20, 30) on the constituent components other than the semiconductor modules is mitigated. The power converter comprises semiconductor modules (20, 30) constituting the main circuit for power conversion, a capacitor (50) electrically connected to the main circuit drive circuit boards (70, 71) each having a drive circuit for supplying a drive signal for operating power conversion to the main circuit, a control circuit board (74) having a control circuit for supplying the control signal for supplying the drive signal to the drive circuits, and a casing containing the above components. In the casing, a cooling chamber having a coolant passage (28) and a peripheral wall defining the chamber and composed of a heat-conductive member is provided. At least the semiconductor modules (20, 30) are contained in the cooling chamber, and at least the capacitor (50) and the control circuit board (74) are installed outside the cooling chamber.