Magnetic field sensor for a position encoder, with at least one magneto-sensitive element which comprises an active surface, at which magneto-sensitive element, during operation, an electric signal is tappable which changes in dependency from the field strength of the component of a magnetic field which is moving due to the motion of a body to be monitored, which component perpendicularly permeates the active surface, and with a ferromagnetic magnetic field deflection unit which is stationary arranged with respect to the at least one magneto-sensitive element, such that the magnetic field deflection unit deflects magnetic field lines which would otherwise run in parallel with respect to the active surface, in a manner that the magnetic field lines permeate the active surface with a component which is perpendicular with respect to the active surface, wherein the magnetic field deflection unit contains at least two ferromagnetic deflection bodies (10, 11; 30, 31, 32, 33; 48, 50, 51, 52; 58, 59, 60) which are arranged in two parallel planes with their facing planar basic surfaces, such that they form at least one overlapping region in which the at least one magneto-sensitive element (3; 24, 25, 26, 27; 40, 41, 42; 55, 56) is located whose active surface runs in parallel with respect to the basic surfaces of the ferromagnetic deflection bodies (10, 11; 30, 31, 32, 33; 48, 50, 51, 52; 58, 59, 60), such that the magneto-sensitive element (3; 24, 25, 26, 27; 40, 41, 42; 55, 56) is perpendicularly permeated by the magnetic field; wherein the at least two ferromagnetic deflection bodies (10, 11; 30, 31, 32, 33; 48, 50, 51, 52; 58, 59, 60) are formed as flat plates; and wherein the magnetic field sensor contains at least four magneto-sensitive elements (24, 25, 26, 27) which are arranged in equal distances with respect to a center point with angular distances to each other and whose active surfaces are in a plane, and wherein the magnetic field deflection unit contains four equal ferromagnetic deflection bodies (30, 31, 32, 33) which comprise the shape of thin circular ring section discs, which are arranged concentrically with respect to the center point, such that respectively two ferromagnetic deflection bodies (30, 32) which are diametrically opposing each other are on the one side, and two ferromagnetic deflection bodies (31, 33) which are diametrically opposing each other are on the other side of the active surfaces, wherein the deflection bodies (30, 31, 32, 33) are overlapping in the regions of their radially running edges, and wherein in each of the thereby formed overlapping regions (35, 36, 37, 38) at least one of the magneto-sensitive elements (24, 25, 26, 27) is arranged. at least one magneto-sensitive element which comprises an active surface, at which magneto-sensitive element, during operation, an electric signal is tappable which changes in dependency from the field strength of the component of a magnetic field which is moving due to the motion of a body to be monitored, which component perpendicularly permeates the active surface, and with a ferromagnetic magnetic field deflection unit which is stationary arranged with respect to the at least one magneto-sensitive element, such that the magnetic field deflection unit deflects magnetic field lines which would otherwise run in parallel with respect to the active surface, in a manner that the magnetic field lines permeate the active surface with a component which is perpendicular with respect to the active surface, wherein the magnetic field deflection unit contains at least two ferromagnetic deflection bodies (10, 11; 30, 31, 32, 33; 48, 50, 51, 52; 58, 59, 60) which are arranged in two parallel planes with their facing planar basic surfaces, such that they form at least one overlapping region in which the at least one magneto-sensitive element (3; 24, 25, 26, 27; 40, 41, 42; 55, 56) is located whose active surface runs in parallel with respect to the basic surfaces of the ferromagnetic deflection bodies (10, 11; 30, 31, 32, 33; 48, 50, 51, 52; 58, 59, 60), such that the magneto-sensitive element (3; 24, 25, 26, 27; 40, 41, 42; 55, 56) is perpendicularly permeated by the magnetic field; wherein the at least two ferromagnetic deflection bodies (10, 11; 30, 31, 32, 33; 48, 50, 51, 52; 58, 59, 60) are formed as flat plates; and wherein the magnetic field sensor contains at least four magneto-sensitive elements (24, 25, 26, 27) which are arranged in equal distances with respect to a center point with angular distances to each other and whose active surfaces are in a plane, and wherein the magnetic field deflection unit contains four equal ferromagnetic deflection bodies (30, 31, 32, 33) which comprise the shape of thin circular ring section discs, which are arranged concentrically with respect to the center point, such that respectively two ferromagnetic deflection bodies (30, 32) which are diametrically opposing each other are on the one side, and two ferromagnetic deflection bodies (31, 33) which are diametrically opposing each other are on the other side of the active surfaces, wherein the deflection bodies (30, 31, 32, 33) are overlapping in the regions of their radially running edges, and wherein in each of the thereby formed overlapping regions (35, 36, 37, 38) at least one of the magneto-sensitive elements (24, 25, 26, 27) is arranged.