To reduce the dimension of a plated resin coil.

A plated resin coil 1 is provided with a cylindrical body 2 equipped with a platable insulating resin and having roots of thread 3 and thread ridges 4. The internal surfaces of the roots of thread 3 are coated with conductive layers 7 composed of plated-copper layers. On the crests of the thread ridges 4, on the other hand, insulating sections 8 which electrically insulate the adjacent conductive layers 7 from each other are mutually formed. As a result, a spirally extending conductive layer, namely, a coil is formed on the outer peripheral surface of the cylindrical body 2.