It is an object of the present invention, which has been made in view of the above-mentioned state of the art, to provide a cement admixture capable of improving the water-reducing ability of cement compositions and the like and enhancing the strength and durability of hardened products produced therefrom and further capable of adjusting the viscosity of such compositions so as to facilitate the works at the sites of handling the same, as well as a method of producing such cement additive.A cement admixture comprising a polycarboxylic acid polymer and a nitrogen atom-containing compound having non-amide bond, wherein the mass ratio (A/B) between the mass (A) of said polycarboxylic acid polymer and the mass (B) of said nitrogen atom-containing compound having non-amide bond satisfies the relation 200>(A/B)>1.