PURPOSE: To prevent a shaft and its bearing from wearing by a method wherein the tension of a belt is made to act only on a pulley, and the structure of an electric cooking device is constituted in such a manner that the tension of the belt is prevented from acting on a high speed shaft and low speed shaft.

CONSTITUTION: When a cooking material which is inputted into a mixer bottle is cooked, the mixer bottle is detachably fitted on a driving unit main body 3, and a power source switch is turned on. By doing so, the rotating force of an electric motor 25 is transmitted to a high speed shaft 14 by a belt 29, pulley 21c of a pulley 21 with a gear, larger diameter gear 21b and second gear 24, and the high speed shaft 14 is rotated at a high speed. By this motion, the cooking material in the mixer bottle is cooked into a desired condition by a rotating cutter. At this time, the tension of the belt 29 acts on the pulley 21 with a gear, but is prevented from acting on the high speed shaft 14. For this reason, a load in the orthogonal direction to the axis does not act on the high speed shaft 14 and a bearing 16, and the high speed shaft 14 and the bearing 16 are prevented from wearing.