A power converter comprising: a DC capacitor; semiconductor switch groups each of which includes two semiconductor switches connected in series to each other; one or a plurality of bridge-cells each of which includes the DC capacitor, and the two semiconductor switch groups that are connected in parallel to the DC capacitor; a delta connection unit at which one or a plurality of bridge-cells are delta-connected, each of the bridge-cells being connected in series to each other; and characterized by a control unit for controlling a circulating current flowing in the delta connection unit such that each of DC-capacitor by-phase average values follows a DC-capacitor three-phase average value, each of the DC-capacitor by-phase average values being obtained by averaging voltage values of the DC capacitors at a corresponding phase of three phases, and the DC-capacitor three-phase average value being obtained by averaging voltage values of the DC capacitors at all of the three phases, wherein the control unit comprises: an averaging control unit for generating a circulating-current command value on the basis of the DC-capacitor three-phase average value and each of the DC-capacitor by-phase average values; and a circulating-current control unit for generating a first command value common to the respective phases for controlling switching operations of the semiconductor switches such that the circulating current follows the circulating-current command value; a balancing control unit that generates a second command value, for the one bridge-cell or each of the plurality of bridge-cells at each of the phases, for controlling switching operations of the semiconductor switches in the corresponding bridge-cell, by using a value that is obtained by multiplying a difference between the DC-capacitor by-phase average value for the corresponding phase and a voltage value of the DC capacitor in the corresponding bridge-cell by a value of an AC current flowing into the corresponding phase; and an electric power control unit that generates a third command value for performing at least one of positive-sequence reactive power control, negative-sequence reactive power control, and active power control. a DC capacitor; semiconductor switch groups each of which includes two semiconductor switches connected in series to each other; one or a plurality of bridge-cells each of which includes the DC capacitor, and the two semiconductor switch groups that are connected in parallel to the DC capacitor; a delta connection unit at which one or a plurality of bridge-cells are delta-connected, each of the bridge-cells being connected in series to each other; and characterized by a control unit for controlling a circulating current flowing in the delta connection unit such that each of DC-capacitor by-phase average values follows a DC-capacitor three-phase average value, each of the DC-capacitor by-phase average values being obtained by averaging voltage values of the DC capacitors at a corresponding phase of three phases, and the DC-capacitor three-phase average value being obtained by averaging voltage values of the DC capacitors at all of the three phases, an averaging control unit for generating a circulating-current command value on the basis of the DC-capacitor three-phase average value and each of the DC-capacitor by-phase average values; and a circulating-current control unit for generating a first command value common to the respective phases for controlling switching operations of the semiconductor switches such that the circulating current follows the circulating-current command value; a balancing control unit that generates a second command value, for the one bridge-cell or each of the plurality of bridge-cells at each of the phases, for controlling switching operations of the semiconductor switches in the corresponding bridge-cell, by using a value that is obtained by multiplying a difference between the DC-capacitor by-phase average value for the corresponding phase and a voltage value of the DC capacitor in the corresponding bridge-cell by a value of an AC current flowing into the corresponding phase; and an electric power control unit that generates a third command value for performing at least one of positive-sequence reactive power control, negative-sequence reactive power control, and active power control.