Patent ID: 8836317

Claim:
A current sensor comprising: a current-measured wiring including parallel wiring sections in which portions of a same wiring are arranged in parallel such that electric current to be measured flows in the parallel wiring sections in opposite directions each other; a magnetism detection unit which is arranged between parallel wirings located in the parallel wiring sections and detects a magnetic field in a direction perpendicular to a plane formed by the parallel wirings; a current detection unit which detects electric current flowing in the current-measured wiring, based on the magnetic field detected by the magnetism detection unit; and a magnetic core surrounding the parallel wiring sections so as to intensify a magnetic field generated around the parallel wirings located in the parallel wiring sections when electric current flows in the parallel wirings, wherein the magnetic core, being configured such that a belt-like body of a constant width is formed to be in an annular shape with rectangular side faces, has a pair of walls facing each other over the plane formed by the parallel wirings and another pair of walls linking the pair of walls of the magnetic core, in which respective whole inner surfaces of the pair of walls are formed to be flat and parallel to the plane formed by the parallel wirings, the magnetism detection unit is arranged between the pair of walls of the magnetic core, and the current sensor further comprises, within the magnetic core, a shield which is opened in a direction perpendicular to the plane formed by the parallel wirings located in the parallel wiring sections, and blocks an external magnetic field in a direction parallel to the plane.