PURPOSE: To improve the transfer characteristics of a minor loop by varying the thickness of a spacer film responding to a bubble transfer direction at the rectilinear part of the minor loop.

CONSTITUTION: The film thickness H and h of a spacer 11 are varied in accordance with the directions A and B where the transfer characteristics of a minor loop are superior and inferior respectively at the rectilinear part of the minor loop formed by a soft magnetic thin film pattern 12. The thickness h is smaller than the thickness H. Therefore the pattern 12 accesses a bubble crystal 10 in the direction B to have larger coupling force than the force in the direction A. This improves the overall transfer characteristics of the minor loop.