PURPOSE: To stabilize the oscillation as well as to reduce the power consumption by connecting the gates of the P- and N-channel MOSFET's connected complementarily to each other to the output side and the power voltage via the high resistance respectively.

CONSTITUTION: Gates 13 and 15 of P- and N-channel MOSFETS10 and 11 which are connected complementarily to each other are connected to output side 12 and power voltage 17 via resistances 14 and 16 respectively. Gates 13 and 15 are also connected to input side 20 via capacitors 18 and 19, and furthermore crystal oscillator 21 plus capacitors 22 and 23 are connected between input side 20 and output side 12. In the oscillator thus constituted, gates 13 and 15 of MOSFETS10 and 11 are biased individually. As a result, the necessary power voltage can be reduced, at the same time stabilizing the oscillation starting performance and reducing the power consumption.