To provide a thermal infrared detecting element that can drive at low voltage and hardly generates noise by hardly changing output due to environmental temperature.

The thermal infrared detecting element comprises an infrared detecting part 901, an element temperature detecting part 301, an input switching switch 304 for switching gate input of an integral transistor 905 between the infrared detecting part and the element temperature detecting part, a bias current supply transistor 101 provided with a holding capacity 103 on a gate, a gate connection switch 102 for connecting a connection point of the bias current supply transistor and the integral transistor to the gate of the bias supply transistor 101, and a coupling capacity 104 ac-coupling the connection point and an integral capacity 907. In a reset period of the integral capacity 907, the input switching switch 304 is connected to the side of the element temperature detecting part. In an integral operation period, the input switching switch 304 is connected to the side of the infrared detecting part to open the gate connection switch 102 while conducting the gate connection switch 102.

COPYRIGHT: (C)2005,JPO&NCIPI