A precise magnetic-field stabilizer using nuclear resonance techniques is proposed and control characteristics of the stabilizer are analyzed in order to obtain conditions for optimizing control. In this control system, the error signal, which is the output voltage of the nuclear resonance magnetic-field detector, is doubly fed back through an anti-hunt circuit (wide-band DC power amplifier) as usual and further through a drift compensating circuit (integrator using a servomotor). According to the analysis, the control system has a short settling time and zero static error to a unit step disturbance. Moreover, the anti-hunt circuit contributes to making the whole system stable as well as to suppressing the field fluctuations, and the drift compensating circuit plays a role of compensating drifts of the static field. Thus the proposed stabilizer is effective for the precise stabilization of magnetic fields over a long duration.