A power conversion device includes an electronic component, a cooler, a housing, protruding pipes, and annular seal members. Each of the seal members includes a seal body portion interposed between a corresponding one of the protruding pipes and the housing, and a flange portion extending outward from the seal body portion in a radial direction and contacting an outer surface of the housing from an axial direction. The housing includes a peripheral wall surface formed to surround the flange portion from an outer peripheral side, and an annular groove portion formed along an outer peripheral edge of the flange portion inside the peripheral wall surface. The peripheral wall surface is formed to extend outward, in the axial direction, from an axial contact surface of the housing contacted by the flange portion.