PURPOSE: To make it possible to detect magnetism accurately without the effect of magnetic fields of noise, by arranging two sets of magnetism sensors, which are magnetically biased in the reverse directions to each other with the phase difference of 180° being provided with respect to a magnetizing pattern.

CONSTITUTION: Magnetoresistance elements Ra1, Ra2, Rb1, and Rb2 are laminated so as to hold insulating films and magnetically biased in the reverse directions each other in two sets of magnetism sensors. The magnetism sensors are aligned in the direction, which is perpendicularly intersected with the arrows of the displacing direction and mounted on a common substrate S. The aligning direction and a magnetizing pattern are relatively inclined in the direction perpendicular to the direction of the arrow. The phase difference of about 180° is imparted to the magnetism sensors with respect to the magnetizing pattern, and bridge connection is performed. The magnetic fields of noise of the two sets of the magnetism sensors are offset, and only the output of the magnetizing pattern can be obtained.