For providing a cleaning technique capable of removing metal contamination at a low temperature and in a short period of time, an aqueous solution containing 0.1 to 15% by weight of hydrochloric acid, 0.01 to 0.3% by weight of hydrofluoric acid and 0.1 to 15% by weight of hydrogen peroxide is used as a cleaning solution for cleaning a semiconductor substrate after forming a gate electrode of a polymetal structure on the semiconductor substrate.