INFRARED GAS ANALYZER

PROBLEM TO BE SOLVED: To maintain high accuracy for a heat-generating position by impressing infrared rays of pulses turned ON or OFF at a gas to be measured, or an optional frequency of sine waves or the like or a periodically continuously increasing/ decreasing voltage change to a light source. SOLUTION: A gas 2 to be measured is introduced from a gas inlet 1a and discharged through a gas outlet 1b. Infrared rays are brought in from an incident window 1c of a measuring cell 1 and projected out from a penetration window 1d. The infrared rays after penetrating the gas to be measured are detected. When infrared rays of pulse lights are emitted, a heat-generating body 5d generates heat at the ON time and stops generating heat at the OFF time, thereby repeatedly shrinking and expanding. Since the heat-generating body 5d is stretched by a spring 5e, the amount of the shrinkage/expansion is absorbed naturally by tone spring 5e, so that a linearity of the heat-generating body 5d at a predetermined position is maintained. Detection accuracy and sensitivity are enhanced because an infrared ray-projecting optical system is stabilized.