<p>A cement admixture that enhances the water reduction and fluidity of cement composition, excelling in slump retention performance. There is provided a cement admixture comprising as essential components two types of copolymers exhibiting a difference of 12 mass% or below in the content (mass%) of carboxylated structural units, whose weight average molecular weights and peak top molecular weights are different from each other. Further, there is provided another cement admixture comprising a polycarboxylic acid polymer having a low-molecular-weight side area ratio (P) of 50 to 87% in the GPC chart thereof.</p>
