A transformer unit comprising a circulating-current reducing circuit (11, 12) to reduce circulating current occurring in the transformer unit, the transformer unit including: a first transformer device; a second transformer device that is connected to the first transformer device in parallel; and a controlling element that controls timing of supply of current to a first primary coil portion on a primary side of the first transformer device and a second primary coil portion on a primary side of the second transformer device, the circulating-current reducing circuit (11, 12) including: a first circuit that is connected between the first primary coil portion on the primary side of the first transformer device and the controlling element; and a second circuit that is connected between the second primary coil portion on the primary side of the second transformer device and the controlling element characterized in that the first circuit and the second circuit each include a first rectifier element (11c, 12c), a first resistance element (11b, 12b), a second rectifier element (11d, 12d), and a second resistance element (11c, 12c), the first circuit is connected to the first primary coil portion in series, the second circuit is connected to the second primary coil portion in series, and in each of the first and the second circuit, the first rectifier element (11c, 12c) and the first resistance element (11b, 12b) are connected in parallel to the second rectifier element (11d, 12d) and the second resistance element (11c, 12c), wherein in the first circuit, a resistance value of the first resistance element and the first rectifier element and a resistance value of the second resistance element and the second rectifier element are each lower than an impedance of the first primary coil portion, and in the second circuit, a resistance value of the first resistance element and the first rectifier element and a resistance value of the second resistance element and the second rectifier element are each lower than an impedance of the second primary coil portion. a first transformer device; a second transformer device that is connected to the first transformer device in parallel; and a controlling element that controls timing of supply of current to a first primary coil portion on a primary side of the first transformer device and a second primary coil portion on a primary side of the second transformer device, the circulating-current reducing circuit (11, 12) including: a first circuit that is connected between the first primary coil portion on the primary side of the first transformer device and the controlling element; and a second circuit that is connected between the second primary coil portion on the primary side of the second transformer device and the controlling element characterized in that the first circuit and the second circuit each include a first rectifier element (11c, 12c), a first resistance element (11b, 12b), a second rectifier element (11d, 12d), and a second resistance element (11c, 12c), the first circuit is connected to the first primary coil portion in series, the second circuit is connected to the second primary coil portion in series, and in each of the first and the second circuit, the first rectifier element (11c, 12c) and the first resistance element (11b, 12b) are connected in parallel to the second rectifier element (11d, 12d) and the second resistance element (11c, 12c), wherein in the first circuit, a resistance value of the first resistance element and the first rectifier element and a resistance value of the second resistance element and the second rectifier element are each lower than an impedance of the first primary coil portion, and in the second circuit, a resistance value of the first resistance element and the first rectifier element and a resistance value of the second resistance element and the second rectifier element are each lower than an impedance of the second primary coil portion. a first circuit that is connected between the first primary coil portion on the primary side of the first transformer device and the controlling element; and a second circuit that is connected between the second primary coil portion on the primary side of the second transformer device and the controlling element characterized in that the first circuit and the second circuit each include a first rectifier element (11c, 12c), a first resistance element (11b, 12b), a second rectifier element (11d, 12d), and a second resistance element (11c, 12c), the first circuit is connected to the first primary coil portion in series, the second circuit is connected to the second primary coil portion in series, and in each of the first and the second circuit, the first rectifier element (11c, 12c) and the first resistance element (11b, 12b) are connected in parallel to the second rectifier element (11d, 12d) and the second resistance element (11c, 12c), wherein in the first circuit, a resistance value of the first resistance element and the first rectifier element and a resistance value of the second resistance element and the second rectifier element are each lower than an impedance of the first primary coil portion, and in the second circuit, a resistance value of the first resistance element and the first rectifier element and a resistance value of the second resistance element and the second rectifier element are each lower than an impedance of the second primary coil portion.