To provide a detergent composition which has little corrosion to a wiring material and is excellent in cleaning ability of a semiconductor substrate or semiconductor device on which the fine particles and the metal impurities are deposited. A detergent composition comprising a reducing agent, wherein the detergent composition has an oxidation-reduction potential at 25.degree. C. of +0.2 V or less, and a pH at 25.degree. C. of from 3 to 12; and a cleaning process of a semiconductor substrate or a semiconductor device using the detergent composition.