<p>Provided is a digitally controlled frequency synthesizer that is insusceptible to disturbance/noise and which does not utilize a ?? modulator. The frequency synthesizer for digitally controlling oscillatory frequencies is provided with: a loop gain adjustment unit (5) that generates digital control data for adjusting the loop gain of said frequency synthesizer; a DA conversion unit (6) that converts the lower bits of the digital control data into an analog voltage; and an oscillation unit (1) that oscillates at a frequency that corresponds to the higher bits of the digital control data and the analog voltage output from the DA conversion unit (6).</p>
