To provide an aqueous composition whose solution viscosity increases through heating.

The composition is prepared by compounding (B) an aqueous resin with (A) a polyoxyalkylene polyol, wherein (B) the aqueous resin is obtained by polymerizing (b1) an acrylamide and (b2) a reactive surfactant having a polymerizable double bond in a molecule. An aqueous solution of the composition thickens through heating.