Abstract: A main tank for preparation of glue having agitation effect and shearing effect far larger than in the conventional tank is fitted with an agitator having multiple blades on a shaft supported to allow rotation on the bottom of a tank. A disc is provided having numerous teeth in the radial direction, with a gap .delta. from the lower surface of the agitating blade. One or more baffles having a triangular cross-section are provided on the inner side surface of the tank and one or more baffles of the same construction are on the bottom. The lower surface of the agitating blade is of a flat shape, and can have teeth at an angle crossing the teeth of the disc. The gap .delta. between the agitating blade and the disc is adjustable.