Electric current measuring coil

This electrical current measurement coil is formed upon a circuit board that has a plurality of conductive layers and insulating layers, which are stacked in an alternating manner, and an opening, which is traversed by a conductor carrying the electric current to be measured, in a manner such that the electric current measurement coil surrounds the opening. The electric current measuring coil has a first coil, which includes two or more conductive patterns formed on two or more conductive layers among the plurality of conductive layers, and a second coil including one or more conductive patterns formed on one or more conductive layers different therefrom among the plurality of conductive layers. When viewed from the stacking direction of the plurality of conductive layers, the winding directions of the first coil and the second coil are reversed, and the area of the region surrounded by the first coil and the area of the region surrounded by the second coil, said regions being affected by magnetic fields that