PURPOSE: To obtain a magnetic bubble detector/eraser with high reliability by making a conductive loop a continuous snaking shape and enlarging an action area.

CONSTITUTION: A current pulse 9a functions to enhance the magnetic field intensity in a center loop of a continuous snaking-shaped conductive loop 4a as shown in a broken line 13 of the figure. Only the impression of the current pulse 9a is not sufficient and unerased magnetic bubbles remain in terms of probability. Since the unerased magnetic bubbles exist in loops at both sides of the conductive loop 4a, a current pulse 9b in the direction of an arrow 5 is impressed on the conductive loop 4a in order to enhance the magnetic field intensity in the conductive loop 4a in the loops at both side, and the unerased magnetic bubbles are removed. A series of operations can almost eliminate erasing errors, but in order to enhance reliability of the erasion operation of a magnetic bubble detector/eraser, a current pulse 9c in the direction of an arrow 7 is impressed on the conductive loop 4a, the magnetic field intensity in the center loop of the conductive loop 4a is improved and an action to erase magnetic bubbles in the center loop is performed.