PURPOSE: To attain a bidirectional shift of a Bloch line pair and at the same time to miniaturize a driving circuit by reducing satisfactorily the fall time of a coil driving current waveform in comparison with its rise time.

CONSTITUTION: A positive polarity coil current 701 has a rise when switches Q1 and Q2 are turned on. When the switches Q1 and Q2 are turned off, the coil current flows to a power supply 605 from a power supply 403 via an R604, a D4, a driving coil 401, an R402, an R603 and a D3 respectively. The fall time of a coil current waveform is less shorter than the rise time. While a negative polarity coil current 702 flows to the power supply 605 via an R602, a D2, the coil 401 and a D1 respectively. If switches Q1, Q2 and Q3, Q4 are controlled by a control signal 705 and a control signal 706 respectively, a coil current 704 is produced. Thus a bidirectional shift is possible for a Bloch line pair.