To manufacture a magnetic toner in such a manner that magnetic powder is uniformly dispersed into a binding resin and that an initial molecular weight is maintained without cutting the molecular chains of the binding resin in a method for manufacturing the magnetic toner.

The binding resin and the magnetic powder are previously kneaded by using a kneading machine M mounted with a uniaxial screw 2 formed with spiral thread ridges 21 in a barrel 1 formed with spiral grooves 11 in such a manner that the thread ridges 21 and the grooves 11 are intermeshed with each other to prepare a prekneaded material. The prekneaded material and another toner materials are further kneaded. Here, the screw is preferably moved back and forth in an axial direction in view of uniformly kneading the binding resin and the magnetic powder without cutting the molecular chains of the binding resin.