Abstract: A current detecting device comprises a substrate, a magnetism sensing member made of ferromagnetic magnetoresistance element, an insulating member, and a conducting member, and these members are formed by a photolithography technique such that the magnetism sensing member is electrically isolated from the conducting member by the insulating member. When a current flows into the conducting member, the magnetism sensing member responds to a magnetic field generated by the current. At this time, the resistance of the magnetism sensing member changes due to a magnetoresistance effect in accordance with the intensity of the current. Therefore, the current can be measured by detecting the resistance change. In such a current detecting device, there is no reactance component thereby achieving high sensitivity when detecting the current.