This power conversion device for a railway vehicle is provided with: a transformer which is electrically connected at a primary winding to an overhead line through a current collector; a main power conversion device which is connected to a secondary winding of the transformer and which is connected to a drive motor; an auxiliary power conversion device which is connected to a tertiary winding of the transformer and which supplies power to an auxiliary device, mounted on the railway vehicle, to be driven; a shutoff device which blocks the electrical connection between the transformer and the overhead line; a detector which is disposed between the overhead line and the shutoff device and which detects whether or not there is power supplied from the overhead line; and a control unit which, while passing through unpowered sections in which, according to output of the detector, no power is supplied at least from the overhead line, in a state in which the shutoff device has interrupted the electrical connection bet
