A power conversion device of modular multilevel conversion type, comprising a plurality of converter cells (5, 6) cascade-connected to each other, the plurality of converter cells including: one or more full bridge-type converter cells (FB, 5); and a plurality of half bridge-type converter cells (HB, 6), each of the plurality of half bridge-type converter cells (HB, 6) including one submodule, each of the one or more full bridge-type converter cells (FB, 5) including two submodules, each of the submodules including: a first terminal, a second terminal and a third terminal, the first to third terminals being provided on or provided to protrude from a surface of a package; a first semiconductor switching element built into the package and connected between the first terminal and the second terminal; a second semiconductor switching element built into the package and connected between the second terminal and the third terminal; and a DC capacitor built into the package and connected between the first terminal and the third terminal, a first full bridge-type converter cell (FB in Fig. 6) included in the plurality of converter cells including a first submodule (40_2) and a second submodule (40_3) as the two submodules, the first terminal of the first submodule (40_2) and the first terminal of the second submodule (40_3) being connected to each other through a wiring, the third terminal of the first submodule (40_2) and the third terminal of the second submodule being connected to each other through a wiring, the second terminal (42_2) of the first submodule (40_2) being used for connection to a second converter cell (HB (40_1) in Fig. 6), the second terminal (42_3) of the second submodule (40_3) being used for connection to a third converter cell (HB (40_4) in Fig. 6) different from the second converter cell. the plurality of converter cells including: one or more full bridge-type converter cells (FB, 5); and a plurality of half bridge-type converter cells (HB, 6), one or more full bridge-type converter cells (FB, 5); and a plurality of half bridge-type converter cells (HB, 6), each of the plurality of half bridge-type converter cells (HB, 6) including one submodule, each of the one or more full bridge-type converter cells (FB, 5) including two submodules, each of the submodules including: a first terminal, a second terminal and a third terminal, the first to third terminals being provided on or provided to protrude from a surface of a package; a first semiconductor switching element built into the package and connected between the first terminal and the second terminal; a second semiconductor switching element built into the package and connected between the second terminal and the third terminal; and a DC capacitor built into the package and connected between the first terminal and the third terminal, a first terminal, a second terminal and a third terminal, the first to third terminals being provided on or provided to protrude from a surface of a package; a first semiconductor switching element built into the package and connected between the first terminal and the second terminal; a second semiconductor switching element built into the package and connected between the second terminal and the third terminal; and a DC capacitor built into the package and connected between the first terminal and the third terminal, a first full bridge-type converter cell (FB in Fig. 6) included in the plurality of converter cells including a first submodule (40_2) and a second submodule (40_3) as the two submodules, the first terminal of the first submodule (40_2) and the first terminal of the second submodule (40_3) being connected to each other through a wiring, the third terminal of the first submodule (40_2) and the third terminal of the second submodule being connected to each other through a wiring, the second terminal (42_2) of the first submodule (40_2) being used for connection to a second converter cell (HB (40_1) in Fig. 6), the second terminal (42_3) of the second submodule (40_3) being used for connection to a third converter cell (HB (40_4) in Fig. 6) different from the second converter cell.