To provide an oscillator circuit which oscillates with a low power consumption and a low oscillator current at a high stability by making loose the coupling of an oscillation loop with a transistor base to lower the base input, using a variable capacitance diode.

The Colpitts oscillator comprises an IC 1 forming an oscillator circuit involving transistors TR1, TR2, a frequency selector circuit composed of capacitors C3, C4, an inductor L1 and capacitors C5, C6, an oscillation loop connected to a crystal via the frequency selector as a feedback input to the base of the transistor TR1 in the IC 1 via a variable capacitance diode D1 and a capacitor 8, a high resistor R3 for grounding the anode of the variable capacitance diode D1, a rectifier/smoother circuit composed of diodes D2, D3, a resistor R1 and a capacitor C10, and a high resistor R2 connected to the cathode of the variable capacitance diode D1.