A rheology control agent for a curable composition includes: a diamide compound (A) and/or a hydrogenated castor oil (A), the diamide compound (A) being obtained by condensation reaction between a diamine component (A1) and a monocarboxylic acid component (A2); and a polyamide compound (B) obtained by polycondensation of an amine component (B1) and a carboxylic acid component (B2). The amine component (B1) contains at least one amine selected from the group consisting of a diamine and a triamine having 2 to 54 carbon atoms. The carboxylic acid component (B2) contains at least one carboxylic acid selected from the group consisting of a dicarboxylic acid and a tricarboxylic acid having 4 to 54 carbon atoms. The polyamide compound (B) is obtained by polycondensation of at least one of the amine component (B1) and the carboxylic acid component (B2) containing polymerized fatty acids.