PURPOSE: To obtain a coil output with excellent high-frequency characteristics by boosting the output of a coil included in a head and by performing phase compensation by a boosting transformer.

CONSTITUTION: The Hall head consists of front chip 2 having a front gap formed, and yoke part 3 and Hall element part 4 constituting a rear chip. The part coupled with Hall element 5 of yoke part 3 is formed in a pointed shape so as to focus magnetic flux. Coil output Vc is led out via transformer 8 that boosts a signal output obtained from coil 7 of yoke part 3 and also performs phase compensation. Further, coil output Vc and Hall output VH obtained from Hall element 5 of Hall element part 4 are supplied to subtracting circuit 9 for subtraction. As the output of subtracting circuit 9, a coil output with excellent high-frequency characteristics can be obtained.