When a developing process is performed, a mixture of developing solution and pure water is supplied while the ratio of developing solution and pure water is gradually increased from pure water to developing solution. Thus, a developing solution component and a resist component gradually react. Even if a resist component dissolves in the mixture of pure water and developing solution, the equality of the concentration of the developing solution can be maintained. Thus, the developing process can be suppressed from being unequally performed. When a rinsing process is performed, a mixture of developing solution and pure water is supplied while the ratio of developing solution against pure water is gradually decreased from developing solution to pure water. Consequently, the substitution from developing solution to pure water can be gradually performed. As a result, particles due to the solidification of unsolved resist can be prevented.