The invention provides a semiconductor washing solution which can suppress occurrence of variation of the shape of a semiconductor device when the semiconductor device is washed and can maintain a stabilized washing capacity for a long period of time. An organic acid ammonium salt is added to a mixed solution of ammonium hydroxide, hydrogen peroxide and water (NH4OH:H2O2:H2O) to prepare the semiconductor washing solution. The organic acid ammonium salt to be added is one or more selected from ammonium acetate, ammonium citrate, ammonium formate and ammonium oxalate. The concentration of the added organic acid ammonium salt ranges from 0.1 mol/l to 20 mol/l.