PURPOSE: To realize the driving principle for a temperature detection circuit to be applied to a portion necessitating the precise temperature detection, which is most suitable for hot water supplier and the like, by employing even a thermistor as a basic element by a method wherein the non-linearity of temperature characteristic, which is the fundamental defect of the thermistor, is compensated.

CONSTITUTION: A temperature detection part 1 consists in connecting a resistor 4 in series and a resistor 3 in parallel to a thermistor 2 and a detection voltage signal Vs is drawn across the ends of the thermistor 2. The non-linear characteristic of the relationship between temperature and resistance value is strikingly improved and said relationship can be regarded substantially as linear by employing the parallel resistor 3 and the series resistor 4 in such a manner as mentined above. When a temperature to be measured is low and consequently the resistance value of the thermistor 2 is high, the relationship between temperature and resistance value is defined by the voltage dividing characteristic of the resistors 3 and 4. On the contrary, when a temperature to be measured becomes high and consequently the resistance value of the thermistor 2 becomes low, the relationship between temperature and resistance value is determined by the resistance values of the thermistor 2 and of the resistor 4 connected in series to the thermistor 2.