A motor driving device comprising: a multi-level converter to receive AC power, thereby outputting multi-level power, the multi-level converter comprising a plurality of diodes (Da, Db, Dc, D'a, D'b, D'c) and a plurality of switching elements; a plurality of capacitors (C dc1, C dc2) to store the multi-level power outputted from the multi-level converter; and a gate drive signal generator to generate gate drive signals for the plurality of switching elements of the multi-level converter, characterized in that: the multi-level converter is configured such that one end of the plurality of capacitors is a floating ground terminal of the gate drive signal generator; and the gate drive signal generator comprises: a gate drive power source (V Gate) to supply a gate drive voltage, a gate driver to generate the gate drive signals, using the gate drive voltage, a first capacitor (C m) for storing the gate drive voltage connected to both power supply terminals of the gate driver, a first switching element (S m) connected between one end of the first capacitor (C m) and said one end of one of the plurality of capacitors (C dc1, C dc2), said first switching element being arranged to perform switching for storing the gate drive voltage, and a diode (D m) and a resistor (R m) connected between the other end of the first capacitor (C m) and a terminal of the gate drive power source (V gate), wherein the diode (D m) prevents backflow of a current to the gate drive power source (V gate). a multi-level converter to receive AC power, thereby outputting multi-level power, the multi-level converter comprising a plurality of diodes (Da, Db, Dc, D'a, D'b, D'c) and a plurality of switching elements; a plurality of capacitors (C dc1, C dc2) to store the multi-level power outputted from the multi-level converter; and a gate drive signal generator to generate gate drive signals for the plurality of switching elements of the multi-level converter, the multi-level converter is configured such that one end of the plurality of capacitors is a floating ground terminal of the gate drive signal generator; and the gate drive signal generator comprises: a gate drive power source (V Gate) to supply a gate drive voltage, a gate driver to generate the gate drive signals, using the gate drive voltage, a first capacitor (C m) for storing the gate drive voltage connected to both power supply terminals of the gate driver, a first switching element (S m) connected between one end of the first capacitor (C m) and said one end of one of the plurality of capacitors (C dc1, C dc2), said first switching element being arranged to perform switching for storing the gate drive voltage, and a gate drive power source (V Gate) to supply a gate drive voltage, a gate driver to generate the gate drive signals, using the gate drive voltage, a first capacitor (C m) for storing the gate drive voltage connected to both power supply terminals of the gate driver, a first switching element (S m) connected between one end of the first capacitor (C m) and said one end of one of the plurality of capacitors (C dc1, C dc2), said first switching element being arranged to perform switching for storing the gate drive voltage, and a diode (D m) and a resistor (R m) connected between the other end of the first capacitor (C m) and a terminal of the gate drive power source (V gate), wherein the diode (D m) prevents backflow of a current to the gate drive power source (V gate). wherein the diode (D m) prevents backflow of a current to the gate drive power source (V gate).