Abstract: A magneto-impedance sensor element includes a magneto-sensitive body having electromagnetic properties that vary by a magnetic field externally acting thereon; and a detection coil wound around the magneto-sensitive body, in which a voltage corresponding to the intensity of the magnetic field acting on the magneto-sensitive body is output from the detection coil by applying a pulse current or a high-frequency current to the magneto-sensitive body. The magneto-sensitive body includes a first magneto-sensitive section and a second magneto-sensitive section that are configured to carry a pulse current or a high-frequency current in opposite directions to each other.