An electric machine includes a stator and a rotor. The stator is disposed near to the rotor and has at least one first stator unit and at least one second stator unit. The first stator unit has a first tooth and a second tooth, and the second stator unit has a third tooth and a fourth tooth. The rotor has a rotating direction or a moving direction with respect to the stator. The first tooth and the third tooth are adjacently disposed to each other along the rotating direction or the moving direction. The protruding directions of the first tooth and the third tooth respectively form a first angle and a third angle with the radial direction of the rotor, and the first angle and the third angle are different.