A power conversion device which converts power between a DC circuit and an AC circuit, the power conversion device comprising: a plurality of leg circuits (8a, 8b, 8c) which correspond to respective phases of the AC circuit and are connected in parallel between common first and second DC terminals (Np, Nn), each leg circuit including: a plurality of converter cells (1, 20) cascaded to one another and each including an energy storage; and at least one inductor (7a, 7b) connected in series to the plurality of converter cells, each of a plurality of specified converter cells which are some of the plurality of converter cells included in each leg circuit including: a capacitor as the energy storage; first and second switching elements (1a, 1b) connected in parallel to the capacitor and connected in series to each other; and third and fourth switching elements (1f, 1g) connected in parallel to the capacitor and connected in series to each other, the capacitor being capable of being charged and discharging through a connection node of the first and second switching elements and a connection node of the third and fourth switching elements; and a control device which controls operations of the plurality of converter cells included in each leg circuit, characterised in that the control device is configured to control operations of the first and second switching elements (1a, 1b) of each specified converter cell based on a circulating current (Icc) which circulates through each leg circuit, wherein the first and second switching elements are exclusively used to control the circulating current, the control device controlling operations of the third and fourth switching elements (1f, 1g) of each specified converter cell based on a voltage of the capacitor (1 e) of each specified converter cell, wherein the third and fourth switching elements are exclusively used to control a difference between a voltage of the cell capacitor and a command value thereof to zero. a plurality of converter cells (1, 20) cascaded to one another and each including an energy storage; and at least one inductor (7a, 7b) connected in series to the plurality of converter cells, each of a plurality of specified converter cells which are some of the plurality of converter cells included in each leg circuit including: a capacitor as the energy storage; first and second switching elements (1a, 1b) connected in parallel to the capacitor and connected in series to each other; and third and fourth switching elements (1f, 1g) connected in parallel to the capacitor and connected in series to each other, the capacitor being capable of being charged and discharging through a connection node of the first and second switching elements and a connection node of the third and fourth switching elements; and a control device which controls operations of the plurality of converter cells included in each leg circuit, characterised in that the control device is configured to control operations of the first and second switching elements (1a, 1b) of each specified converter cell based on a circulating current (Icc) which circulates through each leg circuit, wherein the first and second switching elements are exclusively used to control the circulating current, the control device controlling operations of the third and fourth switching elements (1f, 1g) of each specified converter cell based on a voltage of the capacitor (1 e) of each specified converter cell, wherein the third and fourth switching elements are exclusively used to control a difference between a voltage of the cell capacitor and a command value thereof to zero. a capacitor as the energy storage; first and second switching elements (1a, 1b) connected in parallel to the capacitor and connected in series to each other; and third and fourth switching elements (1f, 1g) connected in parallel to the capacitor and connected in series to each other, the capacitor being capable of being charged and discharging through a connection node of the first and second switching elements and a connection node of the third and fourth switching elements; and a control device which controls operations of the plurality of converter cells included in each leg circuit, characterised in that the control device is configured to control operations of the first and second switching elements (1a, 1b) of each specified converter cell based on a circulating current (Icc) which circulates through each leg circuit, wherein the first and second switching elements are exclusively used to control the circulating current, the control device controlling operations of the third and fourth switching elements (1f, 1g) of each specified converter cell based on a voltage of the capacitor (1 e) of each specified converter cell, wherein the third and fourth switching elements are exclusively used to control a difference between a voltage of the cell capacitor and a command value thereof to zero.