Abstract: An additive for cement comprising the following component (A) is provided. (A) A polycarboxylic acid series esterified copolymer obtained by esterifying a part or whole of carboxylic acid groups of a polycarboxylic acid series copolymer having a polyoxyalkylene chain with a derivative of an alcohol having a polyoxyalkylene chain and represented by the following formula (1) (R1 represents a group of a heterocyclic ring having a nitrogen atom or a group represented by the following formula (2). R2 and R3 represent hydrocarbon groups having 1 to 6 carbon atom(s), respectively and independently. “AO” represents an oxyalkylene group having 2 to 4 carbon atoms. “n1” represents an average mole number of addition of the oxyalkylene group and 1 to 8.).