1. A PLL device comprising:a voltage control oscillation unit that oscillates an output signal in an analog form which has a frequency corresponding to a control voltage;
an analog/digital converter that converts the output signal or a frequency division signal obtained by dividing the output signal by a preset dividing number as a feedback signal into a digital feedback signal;
a quadrature demodulation unit that quadrature-demodulates the digital feedback signal to obtain an in-phase component that is an I component and a quadrature-phase component that is a Q component;
a comparison signal output unit that outputs an I component and a Q component of a digital comparison signal, the digital comparison signal having a set frequency of the output signal when the feedback signal is the output signal and having a frequency obtained by dividing the set frequency by the dividing number when the feedback signal is the frequency division signal;
a phase difference detection unit that obtains a phase difference between the digital feedback signal and the digital comparison signal based on the I component and the Q component of the digital feedback signal and the I component and the Q component of the digital comparison signal;
a loop filter that outputs a control voltage value corresponding to the phase difference obtained at the phase difference detection unit; and
a digital/analog converter that performs a digital-to-analog conversion on the control voltage value obtained at the loop filter and supplies an analog-converted value as a control voltage to the voltage control oscillation unit.