The invention relates to an electric motor, particularly an “external rotor motor”, comprised of a stator housing and a rotor housing which is rotatable with respect to the stator housing, wherein the rotor housing has a cooling ring disposed on its side which axially faces the stator housing, wherein the stator housing and the cooling ring are each provided with a plurality of first and second cooling fins (the second cooling fins also being referred to as “cooling ribs”) which face each other axially and are disposed so as to be distributed in the respective circumferential directions, which fins/ribs collaborate in flow technology when the rotor housing is in rotating operation; wherein, in an axial plan view, the first cooling fins extend radially outwardly, and the second cooling fins (the cooling ribs) are V-shaped and point in the circumferential direction, wherein a rotary relative movement of the first and second cooling fins (the cooling fins and the cooling ribs) generates a cooling air stream, at least between the stator housing and the rotor housing.