PURPOSE: To detect the rotating angles and rotating speeds of a revolving shaft by disposing magnetoresistive elements to the array of magnetization patterns.

CONSTITUTION: The detector consists of a magnetic medium 3, the respective detection heads composed of the MR elements 11 thru 15 and conductor terminals 5 fromed on a substrate 4, the lead wires 6 connected to the terminals 5 and a driving detection circuit 8 having the output terminals 7 to the outside. A leakage magnetic field Hθ so acts to perpendicularly intersect the sence current flowing through the conductors 5 with respect to the magnetization of the MR elements 11 thru 15 and output voltages 11, 12, 13 are obtained for the magnetization patterns 21, 22, 23. If the voltage indicated by V0 close to nearly the center of each of these voltage changes is pulsed as a value, the waveforms 11, 12, 13 are obtained. From the combination chart of these pulses, adressing wherein the minimum read angle Aθ is made a unit is done with the reference point, e.g., θ=0 as a reference, and from the pulse output of each point it is detected at how many degrees from the reference point the medium has rotated.