Thermocouple or thermistor is widely used in order to measure neutral gas temperature in positive column of glow discharge. Since the state of plasma is disturbed by the settings of thermocouple or thermistor, some inaccuracy for measured values cannot be avoided. While, the interference method does not remarkably disturb the state of plasma because of the use of weak laser beam. We compare the data obtained by interference method with those by thermocouple. It is concluded from the comparison that measured values by two different methods almost agree with in the experimental errors in the pressure range from 3 Torr to 40 Torr.