The purpose of the present invention is to provide a viscous composition which is capable of achieving a high viscosity over a pH range from acidic to weakly acidic conditions even in the presence of a polyvalent metal salt by means of an alkyl modified carboxyl group containing water soluble copolymer. A viscous composition which is obtained by adjusting the pH of a liquid composition that contains a specific alkyl modified carboxyl group containing water soluble copolymer a polyvalent metal salt and water to 7.0 or more with use of a base and then adjusting the pH of the resulting liquid composition to 2.5 6.5 with use of a carboxylic acid and/or a phosphorus oxo acid is able to have a high viscosity.
