A voltage controlled oscillator including a resonator which generates an oscillation signal, a frequency of which is in response to a control signal, and an amplifier which amplifies the oscillation signal. Also included is a frequency adjusting mechanism, as well as a voltage control sensitivity mechanism. In one example, the resonator includes an input terminal to which the control signal is applied, a variable capacitance diode and a main inductor. The oscillation frequency adjusting mechanism includes a first variable capacitor, arranged in parallel with the main inductor of the resonator. In addition, the voltage control sensitivity adjusting mechanism includes a second variable capacitor arranged between the input terminal and the amplifying mechanism, and also arranged between a hot terminal of the variable capacitance diode and a hot terminal of the main inductor.