A bidirectional power converter, comprising: a first terminal (11; 111a, 111b, 111c) connectable to an input and output end of a first device that is configured to allow input and output of electric power; a second terminal (13; 113a, 113b, 113c) connectable to an input and output end of a second device that is configured to allow input and output of electric power; a negative terminal (14; 114a, 114b, 114c) connectable to a negative electrode of the second device; a main reactor (22; 122 a, 122b, 122c) having a first end connected to the first terminal (11; 111a, 111b, 111c); a plurality of sub-circuits (5, 6) connected in parallel between a second end of the main reactor (22; 122a, 122b, 122c) and the second terminal (13; 113a, 113b, 113c), each of the sub-circuits (5, 6) including an upper switching element (32, 34) connected to the second terminal (13; 113a, 113b, 113c), and a lower switching element (31, 33) connected between the upper switching element (32, 34) and the negative terminal, an upper diode in antiparallel connection with the upper switching element (32, 34), a lower diode in antiparallel connection with the lower switching element (31, 33), and a sub-reactor (24, 26) having one end connected to the second end of the main reactor (22; 122a, 122b, 122c) and another end connected to a midpoint of a series connection between the upper switching element (32, 34) and the lower switching element (31, 33); and a controller configured sequentially to control each of the sub-circuits (5, 6) to: turn on and turn off the lower switching element (31, 33) and then turn on and turn off the upper switching element (32, 34) in the respective sub-circuit (5, 6), while a current is flowing from the first terminal (11; 111a, 111b, 111c) toward the second terminal (13; 113a, 113b, 113c); and turn on and turn off the upper switching element (32, 34) and then turn on and turn off the lower switching element (31, 33) in the respective sub-circuit (5, 6), while the current is flowing from the second terminal (13; 113a, 113b, 113c) toward the first terminal (11; 111a, 111b, 111c); wherein, when one of the switching elements (31, 32, 33, 34) is turned on, the other switching elements (31, 32, 33, 34) are kept off. a first terminal (11; 111a, 111b, 111c) connectable to an input and output end of a first device that is configured to allow input and output of electric power; a second terminal (13; 113a, 113b, 113c) connectable to an input and output end of a second device that is configured to allow input and output of electric power; a negative terminal (14; 114a, 114b, 114c) connectable to a negative electrode of the second device; a main reactor (22; 122 a, 122b, 122c) having a first end connected to the first terminal (11; 111a, 111b, 111c); a plurality of sub-circuits (5, 6) connected in parallel between a second end of the main reactor (22; 122a, 122b, 122c) and the second terminal (13; 113a, 113b, 113c), each of the sub-circuits (5, 6) including an upper switching element (32, 34) connected to the second terminal (13; 113a, 113b, 113c), and a lower switching element (31, 33) connected between the upper switching element (32, 34) and the negative terminal, an upper diode in antiparallel connection with the upper switching element (32, 34), a lower diode in antiparallel connection with the lower switching element (31, 33), and a sub-reactor (24, 26) having one end connected to the second end of the main reactor (22; 122a, 122b, 122c) and another end connected to a midpoint of a series connection between the upper switching element (32, 34) and the lower switching element (31, 33); and an upper switching element (32, 34) connected to the second terminal (13; 113a, 113b, 113c), and a lower switching element (31, 33) connected between the upper switching element (32, 34) and the negative terminal, an upper diode in antiparallel connection with the upper switching element (32, 34), a lower diode in antiparallel connection with the lower switching element (31, 33), and a sub-reactor (24, 26) having one end connected to the second end of the main reactor (22; 122a, 122b, 122c) and another end connected to a midpoint of a series connection between the upper switching element (32, 34) and the lower switching element (31, 33); and a controller configured sequentially to control each of the sub-circuits (5, 6) to: turn on and turn off the lower switching element (31, 33) and then turn on and turn off the upper switching element (32, 34) in the respective sub-circuit (5, 6), while a current is flowing from the first terminal (11; 111a, 111b, 111c) toward the second terminal (13; 113a, 113b, 113c); and turn on and turn off the upper switching element (32, 34) and then turn on and turn off the lower switching element (31, 33) in the respective sub-circuit (5, 6), while the current is flowing from the second terminal (13; 113a, 113b, 113c) toward the first terminal (11; 111a, 111b, 111c); turn on and turn off the lower switching element (31, 33) and then turn on and turn off the upper switching element (32, 34) in the respective sub-circuit (5, 6), while a current is flowing from the first terminal (11; 111a, 111b, 111c) toward the second terminal (13; 113a, 113b, 113c); and turn on and turn off the upper switching element (32, 34) and then turn on and turn off the lower switching element (31, 33) in the respective sub-circuit (5, 6), while the current is flowing from the second terminal (13; 113a, 113b, 113c) toward the first terminal (11; 111a, 111b, 111c); wherein, when one of the switching elements (31, 32, 33, 34) is turned on, the other switching elements (31, 32, 33, 34) are kept off.