A surfactant solution of the present invention includes a component (a): an α-sulfonated fatty acid ester salt; a component (b): an alkanolamine; a component (c): an aromatic sulfonic acid; and a component (d): water, wherein the content of the component (a) is within a range from 30 to 45 mass %, the molar ratio represented by (b)/(a) is within a range from 0.05 to 0.5, and the molar ratio represented by (b)/(c) is within a range from 0.5 to 2.