To obtain a copolymer latex for paper coating which gives a largely improved polymerization stability at the time of manufacture of the copolymer latex through seed polymerization, which allows small particles to be made with a less addition amount of an emulsifier, which has a good flow property under a high shear, and which can suitable be used as a binder for paper coating.

The manufacturing method of the copolymer latex for paper coating comprises conducting an emulsion polymerization using a seed latex which is obtained by emulsion polymerization using 8-50 pts.wt. of a persulfate per 100 pts.wt. of monomers consisting of 0-100 pts.wt. of an unsaturated carboxylate monomer, 0-20 pts.wt. of an ethylenic unsaturated carboxylic acid monomer and 0-80 pts.wt. of other copolymerizable monomer(s), and which has a Tg of -10 to 100°C and a number average particle diameter of 0.01-0.10 μm.