MAGNETIC DETECTING DEVICE, AND ITS MANUFACTURING METHOD

It is an object of the present invention to provide a magnetic detection device in which, in particular, the environment resistance of the magnetoresistance effect element is improved and a reduction in size is realized and to provide a process of producing the same. The magnetoresistance effect element 10 is entirely covered with an alumina layer 31 except through-holes 31a. Electrode layers 15 and 18 are disposed from the through-holes 31a over the alumina layer 31. A silica layer 32 is disposed on the electrode layers 15 and 18 over the alumina layer 31 on the magnetoresistance effect element 10. Since the alumina layer 31 is formed on the entire top surface of the magnetoresistance effect element 10 before the formation of the electrode layers 15 and 18, unlike a conventional case in which the alumina layer 31 is formed on the magnetoresistance effect elements 10 over the electrode layers through the level difference portions 21 having a steep difference in level, the insulation and protection can be adequately achieved even if the alumina layer 31 has a small thickness. Therefore, the environment resistance of the magnetoresistance effect element can be increased, and the magnetic detection device can be reduced in thickness.