Provided is a transistor oscillating circuit capable of reducing change in oscillating frequency due to change in power supply voltage by improving a base bias circuit of an oscillating transistor 3. In a transistor oscillating circuit, an oscillating circuit 3 of which an emitter is connected to ground through an emitter load resistor 8, a resonance circuit 2 is connected between a base and the ground, and a collector is connected to a power supply terminal, is included, base bias resistors 9 and 10 are connected between the base and the collector and between the base and the emitter of the oscillating transistor 3, and a capacitor 7 is connected between the emitter of the oscillating transistor 3 and AC-ground.