The results of investigating the lower sensitivity threshold of a magnetoresistive transducer converting the magnetic field induction into an electric signal are presented. The voltage fluctuation amplitude measured in terms of the magnetic field induction units amounts to 25 × 10–9 T at the transducer output. It is found that after termination of the action of the magnetic field the output transducer voltage returns to the zero level with a delay. The duration of this return may amount to tens of minutes (depending on the induction and duration of the field action). A digital magnetometer with the scale of ±200 μT graduated to 0.1 μT is fabricated on the basis of the magnetoresistive transducer.