To obtain a latex for paper coating having excellent fluidity, mechanical stability, water retainability, high-speed coating suitability, dry pick and wet pick strength, printing gloss, white paper gloss, hardly decomposable, having excellent preservation stability.

This latex for paper coating is characterized by comprising 100 pts.wt. (calculated as solid content) of a carboxyl-modified styrene-butadiene- based copolymer latex constituted of particles composed of ≥50% particles having 50-150 nm and 0.01-0.2 pt.wt. of a benzisothiazoline-based compound of general formula (1) (R is a hydrogen atom or a 1-8C alkyl group) and a halogenated aliphatic nitro alcohol of general formula (2) (R1 is a hydrogen atom, a halogen atom, a 1-4C alkyl group or a 1-4C alkoxy group; R2 is a hydrogen atom or a 1-4C alkyl group; X is a halogen atom) in the weight ratio of 9/1 to 5/5.