Gas detector

Patent Pending PROBLEM TO BE SOLVED: To detect gas with high accuracy, without being affected by the instability of a constant-voltage source or by the variations in the surrounding temperature. ; SOLUTION: A first gas detector includes a gas detection part, a reference signal output part and a heating control part. The gas detection part has a first semiconductor type gas sensor, a first constant-voltage power supply for allowing a current to flow to the first semiconductor-type gas sensor, a first heating part for inputting a heating signal to heat the first semiconductor-type gas sensor and a first temperature sensor for detecting the temperature of the first heating part.