Method of manufacturing a magnetoresistive sensor

In a method of manufacturing a magnetic sensor by etching a ferromagnetic film on a substrate with an etching solution to form a plurality of magnetoresistive elements of a given width disposed in a row in parallel with each other on the substrate, wherein the magnetoresistive elements are connected by bridge circuits so that the magnetic sensor can be used in proximity to a rotating magnetic member to detect rotation information based upon changes in electrical resistance in the magnetoresistive elements, the improvement comprising the steps of etching the ferromagnetic film to form dummy elements outwardly of each end of the row of magnetoresistive elements so as to allow all of the magnetoresistive elements to be formed of a uniform width by preventing the magnetoresistive elements at each end of the row from being affected by etching solution collected in the spaces outwardly of the ends of the row; where the etching of the dummy elements occurs simultaneously with the etching of the magnetoresistive elements.