PURPOSE: To obtain a 2-input type Schmitt trigger circuit excellent in a temperature characteristic by combining a pair of dual gate electric field effect transistors.

CONSTITUTION: Respective source terminals of a pair of first and second dual gate electric field effect transistors 21 and 22 to switch mutually a current are connected to a common resistance 25 and loads 23 and 23 are connected to respective drain terminals. The drain terminal of a first dual gate electric field effect transistor 21 is connected through a level converting circuit 27 to the second gate of a second dual gate electric field effect transistor 22. Further, the drain terminal of a second dual gate electric field effect transistor 22 is connected through a level converting circuit 30 to the second gate of the first dual gate electric field effect transistor 21. Thus, the characteristic change of a circuit component due to the temperature change does not lose the balance of the circuit from symmetry and the temperature change of the threshold voltage to generate the switching on and off is made very small.