An object is to provide a power conversion device that enables a capacitor element to be efficiently cooled, thus suppressing deterioration of the capacitor element due to heat. The power conversion device includes: a power module including a module body portion storing a semiconductor element, and a power terminal protruding from the module body portion; a capacitor module including a capacitor body portion storing a capacitor element, and a capacitor busbar protruding from the capacitor body portion and connected to the power terminal; and a housing storing the power module and the capacitor module. The housing has a first surface to which the power module is thermally connected, and a second surface to which the capacitor module is thermally connected. A coolant path for cooling the first surface is provided on a back side of the first surface. The capacitor busbar is thermally connected to the first surface.