To provide an MI sensor that can improve the signal-to-noise ratio and operation reliability and, at the same time, can reduce its size, and to provide an IC chip for the sensor and electronic equipment equipped with the sensor.

The IC chip 13 for the MI sensor to which detect signals are supplied from X- and Y-axis MI elements 12X and 12Y is constituted of a pulse generating circuit 21 which generates pulse-like signals, an XY changeover switch 22 which distributes the pulse-like signals, and a switching circuit 24 which is controlled by the distributed pulsed signals and supplies a pulsed exciting current to the MI elements 12X and 12Y. The exciting current is alternately impressed upon the MI elements 12X and 12Y based on the pulsed signals distributed by the switch 22.