Provided is a power conversion device capable of suppressing an increase in cost and an increase in size of the device. A control board 113 that includes a connection unit 140 to which a signal connector 114 which transmits a signal is connected, a base member 120 that supports the control board 113 and has conductivity, and a case 110 that accommodates the control board 113 and the base member 120 and is connected to a ground is provided. The base member 120 includes a supporting portion 141 that is connected to one surface of the control board 113, and a first extending portion 130 of which one end is connected to the supporting portion 141 and the other end extends to the case 110 to be connected to the case 110. An electronic component 113a that generates noise is mounted on the control board 113, and the first extending portion 130 and the supporting portion 141 form an electrical path. The first extending portion 130 is arranged at a position at which a distance between the first extending portion and the electronic component 113a is shorter than a distance between the connection unit 140 and the electronic component 113a.