A power conversion device (100) is configured to comprise a cooler (20) that includes a cooler base (22) provided with a recess serving as a refrigerant flow path (24) on the upper surface side, and acooler upper plate (23) that covers the recess, and that seals the refrigerant flow path (24) by means of a flow path sealing body (26) provided on the outer peripheral portion of the cooler upper plate (23); an upper case (30) that covers the upper surface side of the cooler (20); a lower case (40) that covers the lower surface side of the cooler (20); and a terminal block (52) protruding from the upper surface of the cooler upper plate (23) between the power module (53) on the cooler upper plate (23) in the upper case (30) and the flow path sealing body (26) and serving as a water leakage prevention wall surrounding the power module (53).