To provide a highly reliable and highly sensitive compound semiconductor Hall device which uses InAs as an active layer and shows small variations in a characteristic for a high temperature processing.

A compound semiconductor having the smaller width of a forbidden band is disposed as an active layer 62 between a compound semiconductor layer 62a containing Sb and a second compound semiconductor layer 62c. A first protective layer 64a is formed, and a magnetism sensitive portion is formed using the first protective layer 64a patterned into the shape of the magnetism sensitive portion as a mask, and thereafter sides of the first compound semiconductor layer 62a, the second compound semiconductor layer 62c, and a third compound semiconductor layer 62d, and further the first protective layer 64a are covered with a second protective layer 64b. Part of the active layer 62b is exposed, and the exposed second compound semiconductor layer 62c and the third compound semiconductor layer 62d are covered with a third protective layer 64c. After the protective layers are removed in part, a metal electrode layer 63 is formed. The metal electrode layer 63 comes into contact with a semiconductor thin film 62 only through the active layer 62b.