The multi-level inverter according to the present invention comprises: a group of DC power supplies including three or more DC power supplies which are connected in series with same polarities, a group of terminals including a plurality of terminals for taking desired voltage levels from the opposite end and respective connecting points of group of DC power supplies, a group of switches consisting of switches having open modes and short-circuit modes equal in number to the terminals in the group of the terminals, with respective terminals on the input side being connected to the terminals in the group of terminals and respective terminals on the output side being commonly interconnected, and output terminals connected to the terminals on the output side being commonly interconnected in the group of switches. A contact of a switch connected to a terminal corresponding to desired voltage levels is closed to output voltages at multi-levels to be applied to a load.