Conventional detergents for lithography which contain a surfactant as an active ingredient should have a reduced surfactant concentration because heightened surfactant concentrations result in dissolution of the resin component of a photoresist composition and hence in a dimensional change of a resist pattern. However, the conventional detergents have had a drawback that such a low concentration unavoidably reduces the ability to inhibit pattern falling and defect occurrence. A detergent for lithography is provided which is an aqueous solution containing (A) at least one member selected among nitrogenous cationic surfactants and nitrogenous ampholytic surfactants and (B) an anionic surfactant. This detergent retains a low surface tension even when it has a low concentration. It is effective in inhibiting pattern falling and defect occurrence. It can also inhibit resist patterns from fluctuating in dimension.