In an electrical power conversion device including a step-up or boost converter and an inverter, a small-size and inexpensive power conversion device is provided in which its reactor and capacitors can be made more compact. The electrical power conversion device includes a boost converter connected to an electric energy storage device, an inverter connected on an output side of the boost converter, and a controller for performing a turn-on/turn-off control on semiconductor switching devices of the boost converter and semiconductor switching devices of the inverter; and the semiconductor switching devices of the boost converter are made of an SiC semiconductor, and the semiconductor switching devices of the inverter are made of an Si semiconductor.