PURPOSE: To enable electrification for a higher triboelectric charge level than a conventional method by preliminarily blending a charge controlling additive and a pigment without a solvent, supplying the blended material to an extruder, supplying a resin through a supply port in the downstream of the supply port used for the first blended material, and then extruding the mixed compounded material. CONSTITUTION: This method includes of a process to preliminarily blend a pigment and a charge controlling additive without a solvent, a process to add and blend a resin to the mixture of the pigment and the charge controlling additive, and a process to extrude the mixture of the pigment, the charge controlling additive and the resin. The pigment and the charge controlling additive are supplied to an extruder 1 through a first supply port 13 in the upstream side and preliminarily blended and extruded. Then the resin is supplied to the extruder 1 through a second supply port 14 in the downstream side of the first supply port 13 and blended. Thereby, the obtd. toner can be charged to a higher triboelectric charge level than a toner of the same compsn. produced by a conventional extruding method.