A motor control apparatus comprising: a motor; a motor driving unit comprising: two or more positive-polarity switching devices (31,33) connected with a positive-polarity side of a DC power source, two or more negative-polarity switching devices (32,34) connected with a negative-polarity side of the DC power source, and an output terminal (41,42) provided for each connection point at which one of the positive-polarity switching devices (31,33) and one of the negative-polarity switching devices (32,34) are connected in series with each other, wherein the motor driving unit is configured to supply a current to the motor through the output terminals (41,42); a motor control unit configured to transmit a control signal that controlls the current supplied by the motor driving unit through duty control that turns on and off each of the positive side switching element and the negative side switching element of the motor drive unit; and a cutoff apparatus disposed between the motor control unit and the motor driving unit characterized in that the cutoff apparatus is configured to calculate a current value flowing from the motor driving unit to the motor based on the on time of the duty control cycle of the control signal, and cut off the control signal transmitted from the motor control unit to the motor driving unit, when a calculated current value exceeds an excessive-current determination value. a motor; a motor driving unit comprising: two or more positive-polarity switching devices (31,33) connected with a positive-polarity side of a DC power source, two or more negative-polarity switching devices (32,34) connected with a negative-polarity side of the DC power source, and an output terminal (41,42) provided for each connection point at which one of the positive-polarity switching devices (31,33) and one of the negative-polarity switching devices (32,34) are connected in series with each other, wherein the motor driving unit is configured to supply a current to the motor through the output terminals (41,42); two or more positive-polarity switching devices (31,33) connected with a positive-polarity side of a DC power source, two or more negative-polarity switching devices (32,34) connected with a negative-polarity side of the DC power source, and an output terminal (41,42) provided for each connection point at which one of the positive-polarity switching devices (31,33) and one of the negative-polarity switching devices (32,34) are connected in series with each other, wherein the motor driving unit is configured to supply a current to the motor through the output terminals (41,42); a motor control unit configured to transmit a control signal that controlls the current supplied by the motor driving unit through duty control that turns on and off each of the positive side switching element and the negative side switching element of the motor drive unit; and a cutoff apparatus disposed between the motor control unit and the motor driving unit characterized in that the cutoff apparatus is configured to calculate a current value flowing from the motor driving unit to the motor based on the on time of the duty control cycle of the control signal, and cut off the control signal transmitted from the motor control unit to the motor driving unit, when a calculated current value exceeds an excessive-current determination value.