To provide a developing processor capable of speedy development processing without altering a conventional device structure as much as possible.

The developing processor which performs development processing of a photographic sensitive material P having been exposed is equipped with a magnetic field producing body 11 which applies a magnetic field to at least one of processing liquid and water for performing stabilization processing of the sensitive material P. The magnetic field producing body is arranged in a circulation path for circulating the processing liquid between a stabilization processing liquid tank and a processing liquid supply subtank. The magnetic field is applied to the water to increase it penetrating power, dissolving power, etc., thereby improving stabilization processing capability.