Patent ID: 8610429

Claim:
A magnetic field sensor device comprising: a sensor section that includes a magneto-impedance device having a magnetic amorphous structure; a rod-shaped core section that guides a magnetic field to the magnetic amorphous structure and is disposed in a longitudinal direction with resect to the magnetic amorphous structure; environmental magnetic field cancellation means that generates a correction magnetic field that cancels an environmental magnetic field due to terrestrial magnetism input to the magnetic amorphous structure; observation means that serially observes the magnetic field including a magnetic field signal based on an output from an induced current generating transmitter; storage means that stores observational data observed by the observation means; and correction means that corrects a reference value of the observational data so that the observational data falls within a desired range based on a value obtained by integrating the observational data stored in the storage means for a period in which an integral value of the magnetic field signal based on the output from the induced current generating transmitter is zero.