PURPOSE: To make it possible to obtain a uniformly stirred and kneaded state throughout the total interior of a tank, by a method wherein the stirring effect especially at the tank peripheral wall part of a rotary blade type stirring machine mounted in a shaft type cylindrical tank is enhanced and the inner wall surface of the tank is scraped by a scraper blade.

CONSTITUTION: A support lever 14 is attached to the central shaft of the stirring blade support shaft 13 of a rotary blade type stirring machine 11 provided in a shaft type cylindrical tank 10 so as to be crossed at right angles. A main scraper blade is constituted from a plate shaped member 15, a support member 16 and a scraper 17. In addition, the central shaft of the support lever 14 is inclined at an angles exceeding about 30° to a vertical line and a permeation orifice having a total projection area corresponding to about 1/4 or more of the projection area in a thickness direction is mounted to the support member 16. By this structure, even if a slight number of concave and convex parts are present on the wall of the tank, the scraper blade can scrape the wall of the tank uniformly. In addition, a scraped-up high viscosity substance is passed through the sufficiently large permeation orifice 22 easily to be involved into a turblent stream behind the member 15 and a substance to be stirred in the vicinity of the wall surface is replaced in good efficiency.