A detergent composition which is less apt to corrode wiring materials and is highly effective in cleansing a semiconductor substrate or semiconductor element having fine particles or impurity metal particles adherent thereto. The detergent composition contains a reducing agent and has an oxidation-reduction potential (25 DEG C) of +0.2 V or lower and a pH (25 DEG C) of 3 to 12. Also provided is a method of cleansing a semiconductor substrate or semiconductor element with the detergent composition.
