PURPOSE: To obtain easily the compensation of temperature characteristic over a wide temperature range by connecting the 1st fixed capacitive element in series with a varactor element for temperature compensation and connecting the 2nd fixed capacitive element in parallel with this series circuit.

CONSTITUTION: A circuit connecting a capacitor 10 in parallel with the series circuit comprising capacitors 18, 19 as a load capacitance of an elastic surface wave element 16 is connected to an elastic surface wave oscillator consisting of an amplifier section comprising capacitors 11∼13, resistors 5∼7, a transistor 17 and a constant voltage diode 15 or the like and the elastic surface wave element 16. The capacitor 18 is a varactor diode for temperature compensation and has a large negative quadratic characteristic. The capacitors 19 and 10 are the 1st and the 2nd fixed capacitive elements, and the temperature characteristic of the combined capacitance is set so as to compensate the temperature characteristic of the elastic surface wave oscillator by setting said capacitors 19 and 10.