A nuclear magnetic resonance sensing part applies a high-frequency magnetic field based on an RF signal to a target object and generates an observation signal having a frequency shifted by a frequency of an NMR signal. A mixer part generates an IF demodulation signal including the NMR signal based on an LO signal. Another mixer part generates a pseudo IF signal from the LO signal and the RF signal. A phase detection part detects a specific phase in a waveform of the pseudo IF signal. A physical field generator generates a magnetic field corresponding to the IF demodulation signal that has passed through a low-pass filter. An optical quantum sensor part generates light corresponding to the magnetic field. An ADC digitizes a sensor signal obtained from the light by photoelectric conversion. The optical quantum sensor part performs the quantum operation at a timing of the detected specific phase.