A magnetic sensor 1 comprises a main channel layer 7a having first, second, and third regions 71, 72, 73 and extending in a first direction; a first ferromagnetic layer 12A mounted on the first region 71; a second ferromagnetic layer 12B mounted on the second region 72; a projection channel layer 7b projecting in a direction perpendicular to a thickness direction of the main channel layer 7a from a side face of the third region 73 between the first and second regions 71, 72 in the main channel layer 7a; and a magnetic shield S covering both sides in the thickness direction of the projection channel layer 7b and both sides in the first direction of the projection channel layer 7b and exposing an end face 7c in the projecting direction of the projection channel layer 7b.