To provide a precision detergent composition for using in a washing process of a wash to be washed of glass, wafer or the like, which requires a high surface cleanness, without causing any damage of yellowing, latent flaw or the like on the surface of the wash to be washed, and besides the composition substantially containing no metal ion, no harmful anionic ion such as a halogen ion or the like which causes a bad influence on the surface of the wash to be washed after the washing.

A precision detergent composition comprises quaternary ammonium carbonate and quaternary ammonium hydroxide as a principal component, a washing aqueous solution containing an organic acid as a pH adjustor, and according to demand, at least one surfactant selected from a nonionic surfactant and an anionic surfactant or a complex agent which forms a complex compound from a metal ion, but substantially containing no metal ion.