An oscillation circuit includes a voltage controlled oscillation circuit that includes a variable capacitance circuit provided with a variable capacitance element whose capacitance value is controlled on the basis of a control voltage and oscillates a vibrator so as to generate an oscillation signal, and a fractional N-PLL circuit that receives the oscillation signal generated by the voltage controlled oscillation circuit and includes a voltage controlled oscillator which controls an oscillation frequency on the basis of control input data (an integral division ratio and a fractional division ratio).