PURPOSE: To permit an efficient production of dry toner of a high quality by passing for mixing colored particles and additives through an impact part consisting of rotating and fixing pieces at an ambient temperature of 10 - 90°C.

CONSTITUTION: When preparing a toner by mixing the colored particles having at least binding resin and colorant and additives, the colored particles and the additives are fed at an ambient temperature adjusted to the range of 10 - 90°C through an entrance valve 1 and then through an impact part 10 having a gap (a) of 0.5 - 30mm between a rotating piece and a fixing piece or at least between two kinds of rotating pieces, e.g. a rotating piece 5 and a liner 9. From an exit chamber 11, they are passed through a return passage 12 for recirculation in a device. At the end of the mixing, an article toner is passed through exit chamber 11 and the return passage 12 for recovery from an outlet valve 13. The mixing is ensured by repeating a number of times the impact thereof caused by the rotating pieces and the passage thereof through a small gap. In this way the additive can be adhered to the surfaces of the colored particles in a uniformly and sufficiently dispersed state, thereby making the production of a high quality toner possible.