A high-sensitivity (∼1 fT at a 100-s measurement time) self-generating magnetometer based on the optical orientation of cesium atoms and intended for measurements of absolute values of weak (∼2 × 10^-6 T) magnetic fields is described. Its distinctive feature is the complete optical isolation of the magnetic sensor from the electronic units, allowing one to perform magnetic measurements under conditions of high electromagnetic noise. It is proposed that the magnetometer be used as part of the multichannel system for stabilizing the neutron magnetic resonance in the search for the electrical dipole moment of a neutron.