in a magnetic recording drive having a plurality of magnetic heads each employing a magnetoresistive sensor for the purpose of averaging the time required for sense currents to be caused to flow through the respective magnetoresistive sensors to shorten the longest reproducing time and to suppress the degradation of the characteristics due to the electromigration , thereby improving the reliability of the magnetic recording drive , the magnetic recording drive includes circuits for averaging the useful life depending on the currents caused to flow through the respective magnetoresistive sensors among the plurality of magnetic heads , whereby the time required for the sense current to be caused to flow through one mr reproducing head is greatly shortened . therefore , the levels of outputs of the mr reproducing heads can be increased without reduction of the reliability and thus the reliability of the magnetic recording drive can be improved .