To add components in a state concentrated as much as possible without giving undesirable active loss to processing solution, by specifying the average retention time and the effective term of the processing solution in a specified processing tank.

Developing operation is executed by a device provided with at least one processing tank whose capacity rate to the maximum area of a material which can be housed in it is under 20dm3/m2. Besides, replenishment agent is directly added to the processing solution as a solid together with adding water which can include a small quantity of replenishment reagent. Then, the average retention time of the processing solution in the processing tank is regulated by an expression shown in a figure so as to be shorter than the effective term thereof. The effective term is the term that the Dmax values of red, green and blue exist more than 80% of a value generated by newly adjusted solution. In the expression, V shows the capacity of the processing tank (litter), R shows the replenishment rate (litter/m2), T shows a moving speed (m2/minute) and U shows utilizing efficiency as the percentage of an operation time operating a processor (8 hours/day).