A high-frequency phase-locked oscillation circuit comprising: a magnetoresistive element for oscillating a high-frequency wave with an oscillating frequency f out ; a reference signal source for outputting a reference signal with a reference frequency f ref ; and a phase-locked loop circuit having a phase comparator , a loop filter , and a frequency divider , wherein the frequency divider is adapted to reduce said oscillating frequency f out of the high-frequency wave so as to output a frequency-divided signal f out /N, the phase comparator is adapted to output a phase error signal based on a comparison between the reference signal f ref and the frequency-divided signal f out /N, and the loop filter is adapted to output a voltage A corresponding to the phase error signal, wherein the high-frequency phase-locked oscillation circuit further includes: an adder for adding the voltage A output from the loop filter and a bias voltage B for oscillating the high-frequency wave from the magnetoresistive element, and that inputs an added bias voltage (A+B) to the magnetoresistive element ; and a filter provided between the frequency divider and the magnetoresistive element in a region closer to an input side of the frequency divider, the filter being adapted to cut off the reference frequency f ref while allowing the oscillating frequency f out to pass through the filter . a magnetoresistive element for oscillating a high-frequency wave with an oscillating frequency f out ; a reference signal source for outputting a reference signal with a reference frequency f ref ; and a phase-locked loop circuit having a phase comparator , a loop filter , and a frequency divider , wherein the frequency divider is adapted to reduce said oscillating frequency f out of the high-frequency wave so as to output a frequency-divided signal f out /N, the phase comparator is adapted to output a phase error signal based on a comparison between the reference signal f ref and the frequency-divided signal f out /N, and the loop filter is adapted to output a voltage A corresponding to the phase error signal, wherein the high-frequency phase-locked oscillation circuit further includes: an adder for adding the voltage A output from the loop filter and a bias voltage B for oscillating the high-frequency wave from the magnetoresistive element, and that inputs an added bias voltage (A+B) to the magnetoresistive element ; and a filter provided between the frequency divider and the magnetoresistive element in a region closer to an input side of the frequency divider, the filter being adapted to cut off the reference frequency f ref while allowing the oscillating frequency f out to pass through the filter . an adder for adding the voltage A output from the loop filter and a bias voltage B for oscillating the high-frequency wave from the magnetoresistive element, and that inputs an added bias voltage (A+B) to the magnetoresistive element ; and a filter provided between the frequency divider and the magnetoresistive element in a region closer to an input side of the frequency divider, the filter being adapted to cut off the reference frequency f ref while allowing the oscillating frequency f out to pass through the filter . <EOS>