PURPOSE: To make it possible to uniformly perform the stirring of flowable substance by a stirring rod, by a method wherein the stirring rod is attached to a ring subjected to rotary driving at the eccentric position thereof and made revolvable around the rotary center of the aforementioned ring.

CONSTITUTION: When a speed changeable motor 19 is driven, a stirring rod 22 inserted into the flowable substance in a tank 2 from the upper opening of the tank 2 is rotated and the flowable substance in the tank 2 can be stirred by the stirring blades 22a provided to said stirring rod. In this case, the speed variable motor 19 is subjected to speed control by a handle 21 so that the rotary speed of the stirring rod 22 is delayed when the viscosity of the flowable substance is high and accelerated when the viscosity of the flowable substance is low. By this method, the stirring of the flowable substance with any viscosity can be performed efficiently.