A motor driving device for driving a first permanent magnet synchronous motor and a second permanent magnet synchronous motor, the motor driving device comprising: a converter to generate a direct-current voltage; an inverter to generate a three-phase alternating-current voltage from the direct-current voltage; three first power lines (111u, 111v, 111w) to supply the three-phase alternating-current voltage to the first permanent magnet synchronous motor; three second power lines (112u, 112v, 112w) to supply the three-phase alternating-current voltage to the second permanent magnet synchronous motor; at least two disconnection contactors (108A, 108B) to switch between connection and disconnection of each of at least two (112u, 112w) of the three second power lines (112u, 112v, 112w); characterized by at least two short-circuit contactors (109A, 109B) to switch between connection and disconnection between the two second power lines of each of at least two of pairs of the three second power lines (112u, 112v, 112w); a current sensor to detect a current value of a current flowing through the second permanent magnet synchronous motor; and a controller to control the at least two disconnection contactors (108A, 108B) and the at least two short-circuit contactors (109A, 109B), wherein when stopping driving of the second permanent magnet synchronous motor, the controller switches the at least two disconnection contactors (108A, 108B) from the connection to the disconnection and switches the at least two short-circuit contactors (109A, 109B) from the disconnection to the connection, and wherein after the controller switches the at least two short-circuit contactors (109A, 109B) from the disconnection to the connection, when it is determined that the current value is greater than a predetermined threshold, the controller switches the at least two short-circuit contactors (109A, 109B) from the connection to the disconnection. a converter to generate a direct-current voltage; an inverter to generate a three-phase alternating-current voltage from the direct-current voltage; three first power lines (111u, 111v, 111w) to supply the three-phase alternating-current voltage to the first permanent magnet synchronous motor; three second power lines (112u, 112v, 112w) to supply the three-phase alternating-current voltage to the second permanent magnet synchronous motor; at least two disconnection contactors (108A, 108B) to switch between connection and disconnection of each of at least two (112u, 112w) of the three second power lines (112u, 112v, 112w); characterized by at least two short-circuit contactors (109A, 109B) to switch between connection and disconnection between the two second power lines of each of at least two of pairs of the three second power lines (112u, 112v, 112w); a current sensor to detect a current value of a current flowing through the second permanent magnet synchronous motor; and a controller to control the at least two disconnection contactors (108A, 108B) and the at least two short-circuit contactors (109A, 109B), wherein when stopping driving of the second permanent magnet synchronous motor, the controller switches the at least two disconnection contactors (108A, 108B) from the connection to the disconnection and switches the at least two short-circuit contactors (109A, 109B) from the disconnection to the connection, and wherein after the controller switches the at least two short-circuit contactors (109A, 109B) from the disconnection to the connection, when it is determined that the current value is greater than a predetermined threshold, the controller switches the at least two short-circuit contactors (109A, 109B) from the connection to the disconnection.