A skin cleansing agent composition of the present invention contains an isotropic liquid phase, which is a bicontinuous structure, and containing: 15 to 30 mass % of a nonionic surfactant having HLB of higher than 9 and equal to or lower than 20; 1 to 15 mass % of a nonionic surfactant having HLB of equal to or higher than 5 and equal to or lower than 9; 10 to 40 mass % of an oil agent exhibiting a viscosity at 30 degrees C. of equal to or lower than 30 mPa·s; 10 to 40 mass % of a water-soluble solvent having 3 or more of hydroxyl groups in single molecule; 10 to 30 mass % of a water-soluble solvent having 1 or 2 hydroxyl group(s) in single molecule; 0.05 to 1.0 mass % of a water-soluble polymer containing (meta)acrylic acid as a configuration unit and/or an acryloyl methyl taurate-vinylpyrrolidone copolymer; 0.001 to 2.0 mass % of a water-soluble inorganic salt and/or an organic salt having 1 to 8 carbon atoms; and water.