To provide a voltage controlled oscillator which stably operates in a narrow variation range of the control voltage.

The device is provided with a variable capacity circuit 12 in which voltage control is possible, an inductor circuit 11 with an inductor, a negative resistance circuit 13, and a capacity control circuit 14 which outputs correction voltage. The variable capacity circuit 12, the inductor circuit 11, and the negative resistance circuit 13 are connected in parallel, and compose an oscillation circuit. The capacity control circuit 14 controls so as to correct capacitance in the variable capacity circuit 12 by correction voltage output corresponding to temperature variation in the oscillator circuit and/or power source voltage variation.