the input terminal 3 and the output terminal 4 respectively at least a part of or all the surface of the serial film thermistor 1 are contacted with the bottom of the second film 8 the thickness of the serial film thermistor 1 is h the second film 8 can be a thick film resistor with a low resistance value which is easy for production and features a mature technology for the serial film thermistor 1 having a negative temperature coefficient the temperature coefficient is largely affected by the thickness thereof and it is a difficult problem for a resistor with a low square resistance resistance per square unit and a high temperature coefficient to obtain a low square resistance value and a high temperature coefficient for a fixed size resistor the space between the input terminal 3 and the output terminal 4 is required to be very narrow a space of 0 1 mm can hardly be realized using thick film technology and it is quite easy to implement a thickness of a film thermistor or a resistor of several u03bcm as shown in fig5 the desired equivalent resistance between input terminal 3 and the output terminal 4 can be realized by the serial film thermistor 1 having a negative temperature coefficient and an optimal thickness h along with the second film 8 with different resistance values and thus solve the difficult problem of implementing a thermistor having a negative temperature coefficient with a low square resistance and a high temperature.