In this power conversion device having cell converters (100) connected in series, each cell converter (100a) is provided with: main circuit conductors (3a, 3b) for connecting switching elements (1a, 1b) and a capacitor (2); a bypass portion (4) disposed between two external terminals (X1, X2) connected to other cell converters (100a, 100b); external output conductors (5a, 5b) for connecting the external terminals (X1, X2) and the main circuit conductors (3a, 3b); and bypass connection conductors (6a, 6b) for connecting the external output conductors (5a, 5b) and the bypass portion (4). The high potential sides and low potential sides of the bypass connection conductors (6a, 6b) or the external output conductors (5a, 5b) are disposed facing each other, and regions are provided in which the conductors are bent and the directions of currents flowing through parts of the conductors become the same direction, thereby increasing a mutual inductance and a self-inductance and suppressing short-circuit current flowing through the bypass portion (4) during a double fault.