A power conversion device (1, 1a) for performing power conversion between plural-phase AC and DC, the power conversion device (1, 1a) comprising a plurality of leg circuits each including a positive arm (4u, 4v, 4w) and a negative arm (5u, 5v, 5w) connected in series, the leg circuits being connected in parallel between positive and negative DC buses (2, 3), wherein each of the positive arm (4u, 4v, 4w) and the negative arm (5u, 5v, 5w) in each leg circuit includes at least one first converter cell connected in series, and each first converter cell includes: two series units (22a, 22b) connected in parallel and each composed of a plurality of semiconductor switching elements (20A-20B, 20C-20D) connected in series to each other; and a DC capacitor connected in parallel to the series units (22a, 22b), wherein one of connection portions between the plurality of semiconductor switching elements (20A-20B, 20C-20D) in each series (22a, 22b) unit is used as an output end, the power conversion device (1, 1a) further comprising a circuit breaker for grid interconnection and a charge control unit for controlling initial charging of the DC capacitor in each first converter cell when AC voltage is applied to the power conversion device (1, 1a), wherein the charge control unit includes, for each first converter cell, an element driving unit (30, 30a) for driving, as a startup element, one of the plurality of semiconductor switching elements (20A-20D) in the first converter cell, in the corresponding first converter cell the DC capacitor is arranged to supply each element driving unit (30, 30a) with power and the charge control unit includes a central control unit (32, 32a), wherein the power conversion device is configured to close the circuit breaker such that a charge current flows to each DC capacitor, the central control unit is configured to output a turn-on command to start ON control for each startup element simultaneously, to all the element driving units and each element driving unit (30, 30a) is configured to turn on the start-up element of each first converter cell and keep turned off the other switching elements of each first converter cell, when the voltage of the DC capacitor exceeds a predetermined voltage value, such that the capacitors of only one arm are charged depending on the polarity of the input voltage. each of the positive arm (4u, 4v, 4w) and the negative arm (5u, 5v, 5w) in each leg circuit includes at least one first converter cell connected in series, and each first converter cell includes: two series units (22a, 22b) connected in parallel and each composed of a plurality of semiconductor switching elements (20A-20B, 20C-20D) connected in series to each other; and a DC capacitor connected in parallel to the series units (22a, 22b), wherein one of connection portions between the plurality of semiconductor switching elements (20A-20B, 20C-20D) in each series (22a, 22b) unit is used as an output end, the power conversion device (1, 1a) further comprising a circuit breaker for grid interconnection and a charge control unit for controlling initial charging of the DC capacitor in each first converter cell when AC voltage is applied to the power conversion device (1, 1a), wherein the charge control unit includes, for each first converter cell, an element driving unit (30, 30a) for driving, as a startup element, one of the plurality of semiconductor switching elements (20A-20D) in the first converter cell, in the corresponding first converter cell the DC capacitor is arranged to supply each element driving unit (30, 30a) with power and the charge control unit includes a central control unit (32, 32a), wherein the power conversion device is configured to close the circuit breaker such that a charge current flows to each DC capacitor, the central control unit is configured to output a turn-on command to start ON control for each startup element simultaneously, to all the element driving units and each element driving unit (30, 30a) is configured to turn on the start-up element of each first converter cell and keep turned off the other switching elements of each first converter cell, when the voltage of the DC capacitor exceeds a predetermined voltage value, such that the capacitors of only one arm are charged depending on the polarity of the input voltage.