To provide a development processing device for high silver chloride photographic sensitive materials which is small in size and small in the thickness of a processing tank, and a processing method by which the occurrence of the unequal processing and flaws, etc., of the photosensitive materials is suppressed and which is capable of having stable photographic characteristics even if the photosensitive materials are processed with the processing machine of the small size and the small thickness of the processing tank.

The silver halide photographic sensitive materials for photographing consisting of high silver chloride emulsions having a silver chloride content of 80 to 100mol% are processed by using the processing tank satisfying the conditions V/L≤25 when the tank capacity of the processing section is defined as V milliliter and the path length from the inlet to the outlet of the processing section of the photosensitive materials is defined as L centimeter in the processing method for the silver halide photographic sensitive materials. This development processing device is constituted to satisfy the conditions V/L≤25. The thickness of the processing tank is specified to 0.1 to 10cm and the curvature R formed by the bottom of the processing tank to 0.1≤R≤10mm diameter.