Sense current is applied in pulses, synchronized with the timing clock generated by a clock generator 5, to transducer 2 in the information storage device, reducing the time-averaged value of the sense current. The recorded information on the magnetic disk medium 1 is reproduced by the MR head as reproducing signal pulses in synchronism with the above timing clock. The amplitude of the reproducing signal pulses are proportional to the magnetic field of the magnetic disk medium 1. The reproducing signal pulses are sample-held by a sample-hold circuit 6, and after being digitized by an A/D converter 7, recorded data are retrieved through a demodulator circuit 8 of a partial-response system.