To solve the problem wherein a transistor for constant current is inserted into a current path so that current value becomes fixed for suppressing frequency variation due to temperature variation, and thus, C/N deteriorates in the conventional oscillation circuit, in which current is shared by a buffer amplifier part and an oscillation part.

The oscillation circuit is constituted so that the emitters of buffer amplifier transistors 23, 24 in a buffer amplifier part 2 are connected, a current is applied to an oscillation circuit core part 1 of the emitters via a buffer amplifier emitters resistor 50, a current-compensating resistor 52 and a current-compensating MOS transistor 53 are further connected in series with the emitters and connected to the ground. Then, when the current value of a buffer amplifier is varied by the temperature variation, since the potential of the emitters is raised, current for the portion of the rise in the potential by the current-compensating resistor 52 and the current-compensating MOS transistor 53 flows to the ground and is compensated so that the potential of collectors of oscillation transistors 3, 4 become constant.