To provide a power tool capable of suppressing variations in motor characteristics between external power sources with different voltage while preventing an increase in the size of the power tool. The power tool includes: a motor including a stator on which a plurality of windings are wound and a rotor rotatable relative to the stator; an output unit driven by rotation of the rotor; a power source connection part connectable to an external power source serving as a driving power source of the motor; power source voltage detecting means configured to perform detecting a voltage of the external power source connected to the power source connection part; and connection form changing means configured to perform changing a connection form of the plurality of windings on the basis of the voltage of the external power source.