A blade set for hair clipper which has a lower fixed blade, an upper fixed blade, a movable blade assembly and a blade holder. The movable blade assembly is disposed in between the lower fixed blade and the upper fixed blade and is connected to a driving means driven by a driving unit in the hair clipper to reciprocate laterally relative to the lower fixed blade and the upper fixed blade in an operating condition. A third toothed front edge is provided at a front end of the movable blade assembly. A lower portion of the third toothed front edge cooperates with an upper portion of the first toothed front edge to define a first cutting surface. An upper portion of third toothed front edge cooperates with a lower portion of the second toothed front edge to define a second cutting surface.