To provide a development processing device in which damage to a processing tank, etc., can adequantely be avoided by adequately detecting the overheating state of a heating means and stopping a heating operation when the liquid level of a developer in a development processing tank is abnormally lowered.

An auxiliary solution tank hs to hold the developer near the heat generating part He of a heating means H and the a liquid temperature detecting means 100 (thermostat SS) is provided for maintaining a state where at least part of the heat generating part He of the heating means H and the liquid temperature detecting means 100 to detect the temperature of the developer in the development processing tank 3A come in contact with the developer when the liquid level of the developer in the development processing tank 3A is lowered from an allowable minimum liquid level YG. The heating operation of the heating means H is stopped when heat generated in the heat generating part He of the heating means H conducted to the thermostat SS through the developer and the detected temperature of the thermostat SS exceeds a set temperature.