A motor drive device for driving a brushless DC motor including a rotor and a stator having three-phase windings, the device comprising: an inverter for converting DC electric power to AC electric power and supplying the electric power to the brushless DC motor; a current phase detection unit for detecting a phase of a current flowing through the brushless DC motor; a phase correction unit for outputting a commutation signal for switching a winding to be energized in the brushless DC motor based on a detection result of the current phase detection unit so that a phase of a current flowing in a predetermined winding of the brushless DC motor and a phase of a voltage hold a predetermined relation; a drive unit for outputting a drive signal to the inverter based on the commutation signal output from the phase correction unit, wherein the drive signal indicates a supplying timing of the electric power supplied to the brushless DC motor by the inverter; and a position detection unit for detecting a relative position of the rotor of the brushless DC motor, wherein the phase correction unit comprises: a first commutation unit for outputting a first commutation signal for switching a winding to be energized in the brushless DC motor based on a signal of the position detection unit; a second commutation unit for outputting a second commutation signal for switching a winding to be energized in the brushless DC motor based on a phase of a current detected by the current phase detection unit; a load determination unit for determining a load state of the brushless DC motor; and a switch unit for switching a commutation signal to be output to the drive unit between the first commutation signal and the second commutation signal based on a determination result of the load determination unit, characterized in that the load determination unit further comprises a phase difference determination unit configured to determine a phase difference between a signal of the position detection unit and the second commutation signal, and the switch unit switches the commutation signal to be output to the drive unit from the second commutation signal to the first commutation signal when the phase difference determination unit determines that the phase difference is smaller than a predetermined value. an inverter for converting DC electric power to AC electric power and supplying the electric power to the brushless DC motor; a current phase detection unit for detecting a phase of a current flowing through the brushless DC motor; a phase correction unit for outputting a commutation signal for switching a winding to be energized in the brushless DC motor based on a detection result of the current phase detection unit so that a phase of a current flowing in a predetermined winding of the brushless DC motor and a phase of a voltage hold a predetermined relation; a drive unit for outputting a drive signal to the inverter based on the commutation signal output from the phase correction unit, wherein the drive signal indicates a supplying timing of the electric power supplied to the brushless DC motor by the inverter; and a position detection unit for detecting a relative position of the rotor of the brushless DC motor, wherein the phase correction unit comprises: a first commutation unit for outputting a first commutation signal for switching a winding to be energized in the brushless DC motor based on a signal of the position detection unit; a second commutation unit for outputting a second commutation signal for switching a winding to be energized in the brushless DC motor based on a phase of a current detected by the current phase detection unit; a load determination unit for determining a load state of the brushless DC motor; and a switch unit for switching a commutation signal to be output to the drive unit between the first commutation signal and the second commutation signal based on a determination result of the load determination unit, characterized in that the load determination unit further comprises a phase difference determination unit configured to determine a phase difference between a signal of the position detection unit and the second commutation signal, and the switch unit switches the commutation signal to be output to the drive unit from the second commutation signal to the first commutation signal when the phase difference determination unit determines that the phase difference is smaller than a predetermined value. a first commutation unit for outputting a first commutation signal for switching a winding to be energized in the brushless DC motor based on a signal of the position detection unit; a second commutation unit for outputting a second commutation signal for switching a winding to be energized in the brushless DC motor based on a phase of a current detected by the current phase detection unit; a load determination unit for determining a load state of the brushless DC motor; and a switch unit for switching a commutation signal to be output to the drive unit between the first commutation signal and the second commutation signal based on a determination result of the load determination unit, characterized in that the load determination unit further comprises a phase difference determination unit configured to determine a phase difference between a signal of the position detection unit and the second commutation signal, and the switch unit switches the commutation signal to be output to the drive unit from the second commutation signal to the first commutation signal when the phase difference determination unit determines that the phase difference is smaller than a predetermined value.