To provide a cleaning method with the throughput of whole cleaning treatment improved by eliminating the splashing of a chemical solution to be introduced into a treatment tank, reducing the number of places where the solution is splashed in the tank, and decreasing the number of places where the residual solution in the tank is removed by pure water after the treatment and an apparatus for the method.

The plashing of the chemical solution is prevented by installing splashing prevention means 14, 15 in the tip part of a pipe line introduced into the treatment tank 4 and the bottom part of the tank 4 facing the tip part, respectively.