To minimize the decrease in the pick strength of coated paper and to improve high shear fluidity by setting up the average particle size of a water- insoluble higher fatty acid metal salt in a specified range.

The average particle size of a substantially water-insoluble higher fatty acid metal salt, excluding salts of alkali metals, ammonium, or the like, of saturated fatty acids such as caprylic acid, lauric acid, myristic acid, palmitic acid, stearic acid, arachinic acid, and behenic acid of the number of carbon atoms of at least 8 and unsaturated fatty acids such as octenoic acid, tetradecenoic acid, hexadecenoic acid, linoleic acid, and linolenic acid is set up at 0.05-0.7 μm. In this way, the decrease in the pick strength of coated paper is minimized, high shear fluidity can be improved, and the generation of an aggregate during high speed coating can be prevented.