Provided is a technique for mass-producing a conductor to which is fixed a current detection head that detects the value of current flowing in the conductor, and in which the relationship between the detection value and the current value is stabilized. The head comprises a lens, a magneto-optical element, a conductor, and a fixing member, and the lens, the magneto-optical element, and the conductor are respectively fixed to the fixing member. An optical system is formed using the current detection head such that light is guided through the lens to the magneto-optical element, and light affected by a magneto-optical effect due to the magneto-optical element is guided to the lens. All of the members contributing to current detection are fixed to the fixing member, and therefore the relative positional relationships of all the members contributing to current detection are uniquely determined, enabling conductors with little variation in current detection characteristics to be mass-produced. A shape for determining the positional relationship between the fixing member and the conductor may be formed therebetween in advance, and the positioned current detection head and conductor may be fixed to obtain the conductor.