A power conversion device comprising: - a conversion circuit (10, 10A, 10B, 10C, 10E, 10F, 20, 20A, 50, 50D) having a capacitor (2, 2a, 2b) and a bridge circuit (13(12a-12b, 22a-22b)) in which a plurality of switching elements (1 (1a1, la2, 1a3, Ibl, lb2, lb3, 1c1, lc2, lc3, 1d1, ld2, ld3)) are connected including series connections and parallel connections; and - an external stacked conductor having a P conductor (4A-4F) connected to a positive electrode of the capacitor (2, 2a, 2b), an N conductor (5A-5F) connected to a negative electrode of the capacitor (2, 2a, 2b), an AC conductor (6A-6F) connected to an intermediate terminal of the bridge circuit (13(12a-12b, 22a-22b)), and an even number of intermediate conductors (7A-7F) connected between the plurality of switching elements to form the series and parallel connections, such that the P conductor (4A-4F), the N conductor (5A-5F), the AC conductor (6A-6F), and the intermediate conductors (7A-7F) are arranged in a plurality of layers, the external stacked conductor making connection among positive terminals and negative terminals of the switching elements, the positive electrode and the negative electrode of the capacitor (2, 2a, 2b), and the intermediate terminal of the bridge circuit (13(12a-12b, 22a-22b)) in accordance with a circuit configuration of the conversion circuit (10, 10A, 10B, 10C, 10E, 10F, 20, 20A, 50, 50D), wherein the plurality of switching elements in the bridge circuit (12a-12b) form an upper arm element group (12a, 22a) connected between the positive electrode of the capacitor and the intermediate terminal, and a lower arm element group (12b, 22b) connected between the negative electrode of the capacitor and the intermediate terminal, wherein the plurality of switching elements are arranged symmetrically with respect to a center line (m) in the external stacked conductor which is in a same direction as a main current flowing through the external conductor from the capacitor (2, 2a, 2b) to the P conductor (4A-4F) or from the N conductor (5A-5F) to the capacitor (2, 2a, 2b), characterized in that the respective switching elements are arranged such that a mutual positional relationship between the positive terminal and the negative terminal of each switching element is the same as a direction of the main current flowing through the external stacked conductor and external connection terminals are provided to the AC conductor (6A-6F), so as to be positioned symmetrically with respect to the center line (m). - a conversion circuit (10, 10A, 10B, 10C, 10E, 10F, 20, 20A, 50, 50D) having a capacitor (2, 2a, 2b) and a bridge circuit (13(12a-12b, 22a-22b)) in which a plurality of switching elements (1 (1a1, la2, 1a3, Ibl, lb2, lb3, 1c1, lc2, lc3, 1d1, ld2, ld3)) are connected including series connections and parallel connections; and - an external stacked conductor having a P conductor (4A-4F) connected to a positive electrode of the capacitor (2, 2a, 2b), an N conductor (5A-5F) connected to a negative electrode of the capacitor (2, 2a, 2b), an AC conductor (6A-6F) connected to an intermediate terminal of the bridge circuit (13(12a-12b, 22a-22b)), and an even number of intermediate conductors (7A-7F) connected between the plurality of switching elements to form the series and parallel connections, such that the P conductor (4A-4F), the N conductor (5A-5F), the AC conductor (6A-6F), and the intermediate conductors (7A-7F) are arranged in a plurality of layers, the external stacked conductor making connection among positive terminals and negative terminals of the switching elements, the positive electrode and the negative electrode of the capacitor (2, 2a, 2b), and the intermediate terminal of the bridge circuit (13(12a-12b, 22a-22b)) in accordance with a circuit configuration of the conversion circuit (10, 10A, 10B, 10C, 10E, 10F, 20, 20A, 50, 50D), wherein the plurality of switching elements in the bridge circuit (12a-12b) form an upper arm element group (12a, 22a) connected between the positive electrode of the capacitor and the intermediate terminal, and a lower arm element group (12b, 22b) connected between the negative electrode of the capacitor and the intermediate terminal, wherein the plurality of switching elements are arranged symmetrically with respect to a center line (m) in the external stacked conductor which is in a same direction as a main current flowing through the external conductor from the capacitor (2, 2a, 2b) to the P conductor (4A-4F) or from the N conductor (5A-5F) to the capacitor (2, 2a, 2b), characterized in that the respective switching elements are arranged such that a mutual positional relationship between the positive terminal and the negative terminal of each switching element is the same as a direction of the main current flowing through the external stacked conductor and external connection terminals are provided to the AC conductor (6A-6F), so as to be positioned symmetrically with respect to the center line (m).