As a result of the expanding applications of electronic devices for consumers appliances, thermistor sensors have rapidly begun to be used in many homes. It is supposed that the total quantity of the thermistor sensors produced in Japan in a year amounts to 30 million pcs. Since the mass-production of accurate thermistors for instruments has been achieved to meet the needs timely. The applications of thermistors are expanding, applications for microwave oven ranges, kerosene for heaters, plain paper copy machines, and electronic clinical thermometers are explained and also the thermistor humidity sensors with which absolute humidity can be measured are introduced. By detecting sudden increase in water vapor pressure with the thermistor humidity sensors, progress of the cooking can be detected, and very good controlled results are obtained.