A cleaning equipment generally comprises: a cleaning bath 30 for storing therein a cleaning solution to allow a semiconductor wafer W to be dipped in the cleaning solution to clean the surface of the wafer W; a cleaning solution supply pipe 33 for connecting the cleaning bath 30 to a pure water supply source 31; a chemical storing container 34 for storing therein a chemical; a chemical supply pipe 36 for connecting the cleaning solution supply pipe 33 to the chemical storing container 34 via an injection shut-off valve 35; and a diaphragm pump 37 for injecting a predetermined amount of chemical from the chemical storing container 34 into pure water flowing through the cleaning solution supply pipe 33. The temperature of the cleaning solution in the cleaning bath 30 is detected by, e.g., a temperature sensor 44. On the basis of a detection signal outputted from the temperature sensor 44, the amount of the chemical injected by the diaphragm pump 37 is controlled so that the concentration of the chemical is a predetermined concentration. Thus, a predetermined amount of chemical can be injected so as to clean the wafer W with a predetermined concentration of chemical.