A reciprocation driving device is adapted to be mounted in a housing (90) of a hair clipper for reciprocating a moving blade (92) of a blade assembly (92, 93) , and includes a stator unit (20) and a rotor unit (30) . The stator unit (20) has a tubular shaft (21) to permit a spindle (31) of the rotor unit (30) to be rotatably mounted therein by virtue of a pair of bearings (40), a bracing member (22) disposed to be engaged with the housing (90), and a coil winding assembly (24) disposed on the tubular shaft (21) . The rotor unit (30) has a carrier member (33) extending radially and outwardly from a spindle end (312) of the spindle (31) to carry a permanently magnetic member (32) so as to generate a torque as a result of electromagnetic forces acting between the rotor and stator units (20, 30) .
