A power conversion apparatus, comprising: a channel case having a cooling channel built therein, a two-sided cooling semiconductor module having built therein an upper and lower arm series circuit of an inverter circuit, a capacitor module, a direct-current, DC, connector, and an alternative-current, AC, connector, characterized in that the two-sided cooling semiconductor module has a first and a second heat radiating metal (522, 562) in each of which one surface is a heat radiating surface, the upper and lower arm series circuit being hermetically disposed between the first and second heat radiating metals (522, 562), and has a direct-current, DC, positive electrode terminal, a direct-current, DC, negative electrode terminal, and an alternating current terminal that protrude externally; an opening is provided in the channel case; a plurality of the two-sided cooling semiconductor modules are disposed such that the first and second heat radiating metals (522, 562) of the two-sided cooling semiconductor modules are inserted inside the cooling channel from the opening; insulating members (524, 564) are respectively disposed on an other surface of each of the first and second heat radiating metals (522, 562) of the two-sided cooling semiconductor module, and a plurality of semiconductor chips for constituting an upper and lower arm series circuit are disposed between the insulating members (524, 564); on the inside of the two-sided cooling semiconductor module are respectively disposed a direct-current, DC, positive electrode conductor, a direct-current, DC, negative electrode conductor, and an alternating current conductor that electrically connect, respectively, the plurality of semiconductor chips and the DC positive electrode terminal, the DC negative electrode terminal, and the alternating current terminal; and the DC positive electrode terminal and the DC negative electrode terminal of the two-sided cooling semiconductor module are respectively electrically connected to a terminal of the capacitor module and electrically connected to the DC connector, and the alternating current terminals of the plurality of two-sided cooling semiconductor modules are respectively electrically connected to the AC connector. a channel case having a cooling channel built therein, a two-sided cooling semiconductor module having built therein an upper and lower arm series circuit of an inverter circuit, a capacitor module, a direct-current, DC, connector, and an alternative-current, AC, connector, characterized in that the two-sided cooling semiconductor module has a first and a second heat radiating metal (522, 562) in each of which one surface is a heat radiating surface, the upper and lower arm series circuit being hermetically disposed between the first and second heat radiating metals (522, 562), and has a direct-current, DC, positive electrode terminal, a direct-current, DC, negative electrode terminal, and an alternating current terminal that protrude externally; an opening is provided in the channel case; a plurality of the two-sided cooling semiconductor modules are disposed such that the first and second heat radiating metals (522, 562) of the two-sided cooling semiconductor modules are inserted inside the cooling channel from the opening; insulating members (524, 564) are respectively disposed on an other surface of each of the first and second heat radiating metals (522, 562) of the two-sided cooling semiconductor module, and a plurality of semiconductor chips for constituting an upper and lower arm series circuit are disposed between the insulating members (524, 564); on the inside of the two-sided cooling semiconductor module are respectively disposed a direct-current, DC, positive electrode conductor, a direct-current, DC, negative electrode conductor, and an alternating current conductor that electrically connect, respectively, the plurality of semiconductor chips and the DC positive electrode terminal, the DC negative electrode terminal, and the alternating current terminal; and the DC positive electrode terminal and the DC negative electrode terminal of the two-sided cooling semiconductor module are respectively electrically connected to a terminal of the capacitor module and electrically connected to the DC connector, and the alternating current terminals of the plurality of two-sided cooling semiconductor modules are respectively electrically connected to the AC connector.