A magnetic balance type current sensor comprising: a magnetoresistance effect element (122a, 122b) whose resistance value changes owing to the application of an induction magnetic field from a current to be measured; a feedback coil disposed in the vicinity of the magnetoresistance effect element (122a, 122b) and generating a cancelling magnetic field cancelling out the induction magnetic field; a magnetic field detection bridge circuit comprising the magnetoresistance effect element (122a, 122b) and including two outputs causing a voltage difference to occur, the voltage difference corresponding to the induction magnetic field; and a magnetic shield attenuating the induction magnetic field and enhancing the cancelling magnetic field, wherein a current is applied to the feedback coil on the basis of the voltage difference and, on the basis of the current flowing through the feedback coil at the time of an equilibrium state in which the induction magnetic field and the cancelling magnetic field are cancelled out, the current to be measured is measured, wherein the feedback coil, the magnetic shield, and the magnetic field detection bridge circuit are formed on a same substrate, characterised in that the feedback coil is disposed between the magnetic shield and the magnetic field detection bridge circuit, and the magnetic shield is disposed on a side near the current to be measured, and the feedback coil is configured using a planar coil, and the planar coil is provided so that both the induction magnetic field and the cancelling magnetic field occur in a plane parallel to a forming surface of the planar coil. a magnetoresistance effect element (122a, 122b) whose resistance value changes owing to the application of an induction magnetic field from a current to be measured; a feedback coil disposed in the vicinity of the magnetoresistance effect element (122a, 122b) and generating a cancelling magnetic field cancelling out the induction magnetic field; a magnetic field detection bridge circuit comprising the magnetoresistance effect element (122a, 122b) and including two outputs causing a voltage difference to occur, the voltage difference corresponding to the induction magnetic field; and a magnetic shield attenuating the induction magnetic field and enhancing the cancelling magnetic field, wherein a current is applied to the feedback coil on the basis of the voltage difference and, on the basis of the current flowing through the feedback coil at the time of an equilibrium state in which the induction magnetic field and the cancelling magnetic field are cancelled out, the current to be measured is measured, wherein the feedback coil, the magnetic shield, and the magnetic field detection bridge circuit are formed on a same substrate, characterised in that the feedback coil is disposed between the magnetic shield and the magnetic field detection bridge circuit, and the magnetic shield is disposed on a side near the current to be measured, and the feedback coil is configured using a planar coil, and the planar coil is provided so that both the induction magnetic field and the cancelling magnetic field occur in a plane parallel to a forming surface of the planar coil.