To reduce a size of a connector.

A core 33 comprises a pillar-like internal core 35 located on an inner peripheral side of the coil 32 and a pillar-like external core 36 located on an outer peripheral side of the coil 32. As the pillar-like external core 36 is formed not in a cylindrical manner but in a pillar-like manner, a thickness (diametric dimension) of the external core 36 is relatively large so as to withstand a baking formation, while a sectional area of a magnetic path of the external core 36 can be restricted to be small. Thus, the external core 36 is not larger than required, and it is possible to effectively realize reduction in size as a whole of a connector and also to reduce a weight thereof.