Provided is a cement additive that can suppress the production of Glauber's salt as a by-product, and that can express excellent retention when turned into a cement composition. Also provided is a cement composition including such cement additive. Also provided is a raw material for a cement additive to be used in such cement additive. The cement additive of the present invention includes: a polycarboxylic acid-based copolymer (A) having a structural unit (I) derived from an unsaturated polyalkylene glycol-based monomer (a) represented by the specific general formula (1) and a structural unit (II) derived from an unsaturated carboxylic acid-based monomer (b) represented by the specific general formula (2); and an alkanolamine compound (B), in which a content of the structural unit (II) with respect to a total amount of the structural unit (I) and the structural unit (II) is 60 mol % or less.