A micro magnetic sensor, comprising: a magnetic field detection element including a substrate having a groove, two conductive magnetic wires (21, 22) for magnetic field detection arranged adjacent and parallel to each other on the substrate and fixed in the groove, the lower ends of the two magnetic wires (21, 22) are connected through a wire connection part, two electrodes (24, 25) for wire energization, a connection part between the magnetic wires (21, 22) and the two electrodes (24, 25) for wire energization, a round coil wound around the two magnetic wires (21, 22), two electrodes (34, 35) for coil voltage detection, and a connection part between the coil and the two electrodes (34, 35) for coil voltage detection; a pulse current applying circuit configured to apply a pulse current to the magnetic wires (21,22); a coil voltage detecting circuit configured to detect a coil voltage occurred when the pulse current is applied to the two magnetic wires (21,22); and a voltage converting circuit (55 and 58) configured to convert the coil voltage into an external magnetic field H, wherein the two conductive magnetic wires (21, 22) have a magnetic anisotropy field of 20 G or less, with a two-phase magnetic domain structure of a surface magnetic domain with circumferential spin alignment and a center core magnetic domain with longitudinal spin alignment, and the pulse current applied to the magnetic wires (21, 22) has a pulse frequency of 0.2 GHz to 4.0 GHz and a strength required to generate an over 1.5 times larger circumferential magnetic field than the anisotropy field on a surface of the wire, and the coil has a coil pitch of 10 μm or less, characterized in that, in the magnetic field detection element, the two conductive magnetic wires (21, 22) are arranged over a lower part of the coil, and are fixed and covered by an insulating resin, an upper part of the coil is provided on the insulating resin, the one round coil is wound around the two magnetic wires (21, 22), and an insulating separation wall is arranged between the two magnetic wires (21, 22). a magnetic field detection element including a substrate having a groove, two conductive magnetic wires (21, 22) for magnetic field detection arranged adjacent and parallel to each other on the substrate and fixed in the groove, the lower ends of the two magnetic wires (21, 22) are connected through a wire connection part, two electrodes (24, 25) for wire energization, a connection part between the magnetic wires (21, 22) and the two electrodes (24, 25) for wire energization, a round coil wound around the two magnetic wires (21, 22), two electrodes (34, 35) for coil voltage detection, and a connection part between the coil and the two electrodes (34, 35) for coil voltage detection; a pulse current applying circuit configured to apply a pulse current to the magnetic wires (21,22); a coil voltage detecting circuit configured to detect a coil voltage occurred when the pulse current is applied to the two magnetic wires (21,22); and a voltage converting circuit (55 and 58) configured to convert the coil voltage into an external magnetic field H, wherein the two conductive magnetic wires (21, 22) have a magnetic anisotropy field of 20 G or less, with a two-phase magnetic domain structure of a surface magnetic domain with circumferential spin alignment and a center core magnetic domain with longitudinal spin alignment, and the pulse current applied to the magnetic wires (21, 22) has a pulse frequency of 0.2 GHz to 4.0 GHz and a strength required to generate an over 1.5 times larger circumferential magnetic field than the anisotropy field on a surface of the wire, and the coil has a coil pitch of 10 μm or less, characterized in that, in the magnetic field detection element, the two conductive magnetic wires (21, 22) are arranged over a lower part of the coil, and are fixed and covered by an insulating resin, an upper part of the coil is provided on the insulating resin, the one round coil is wound around the two magnetic wires (21, 22), and an insulating separation wall is arranged between the two magnetic wires (21, 22). the two conductive magnetic wires (21, 22) have a magnetic anisotropy field of 20 G or less, with a two-phase magnetic domain structure of a surface magnetic domain with circumferential spin alignment and a center core magnetic domain with longitudinal spin alignment, and the pulse current applied to the magnetic wires (21, 22) has a pulse frequency of 0.2 GHz to 4.0 GHz and a strength required to generate an over 1.5 times larger circumferential magnetic field than the anisotropy field on a surface of the wire, and the coil has a coil pitch of 10 μm or less, characterized in that, in the magnetic field detection element, the two conductive magnetic wires (21, 22) are arranged over a lower part of the coil, and are fixed and covered by an insulating resin, an upper part of the coil is provided on the insulating resin, the one round coil is wound around the two magnetic wires (21, 22), and an insulating separation wall is arranged between the two magnetic wires (21, 22).