An object of the present invention is to provide an easy-to-handle, before and after dilution with water, concentrated liquid cleanser composition and a production method thereof.A concentrated cleanser composition of the present invention is characterized by comprising: (A) an anionic surfactant, (B) an amphoteric surfactant, (C) 5 to 15 mass % of a monohydric or dihydric alcohol, (D) 8 to 18 mass % of a nonionic surfactant with the IOB value of 0.8 to 1.1 and the molecular weight of 500 or lower, and (E) 45 mass % or less of water, wherein the sum of (A) and (B) is 40 to 60 mass % wherein the blending ratio (C):(D) is 3.5:1 to 1:2.5 and wherein the viscosity at 30 °C is 300 mPa • s or higher when the composition is diluted until the concentration of (A) and (B) becomes 15 mass %.
