To provide a development processor which can efficiently control the temperature of process liquid, in a process liquid tank having no temperature control device, although the developing device has a simple constitution.

The developing device is equipped with a plurality of processing liquid tanks to reserve processing liquids, with one of the processing liquid tanks being equipped with a temperature control device for controlling the temperature of a reserved processing liquid to a predetermined temperature, where a barrier wall between adjoining processing liquid tanks is made of a material having high thermal conductivity so as to transfer heat in a processing liquid in one processing liquid tank of the tanks interposing the barrier wall to a processing liquid in the other processing liquid tank via the barrier wall. The processing liquid tank is composed of a main tank and a pair of sub tanks, disposed on both sides of the main tank. The process tank is equipped with a circulating device, comprising a communicating passage connecting the sub tanks; a pump device for supplying a processing liquid in one sub tank into the other sub tank via the communication passage; and a circulation hole for a processing liquid formed in a compartment wall between the sub tank and the main tank, near the barrier wall.