A power conversion device includes a semiconductor module, first and second electrical components, a housing, and a cooler. The semiconductor module has a signal terminal connected to a board. A bottom of the housing has a first placement portion in which the semiconductor module is disposed on an inner bottom surface side and the second electrical component is disposed on an outer bottom surface side, and a second placement portion that is farther from the board than the first placement portion and in which the first electrical component is disposed on an inner bottom surface side. The first placement portion includes, inside thereof, a second flow path adjacent to the semiconductor module, a third flow path adjacent to the second electrical component, and a wall separating the second flow path and the third flow path. The semiconductor module is sandwiched between the cooler and the first placement portion.