A common mode choke coil includes two extraction conductors formed on a
resin insulating layer, and a concave portion is formed in the resin
insulating layer in an area between a first portion covered with one of
the extraction conductors and a second portion covered with the other
extraction conductor. An upper resin insulating layer is embedded inside
the concave portion. Accordingly, because the resin insulating layer is
not flat in the portion where the extraction conductors are formed, a
distance between the extraction conductors along the surface of the resin
insulating layer increases. Therefore, a current path generated due to
ion migration along the surface of the insulating layer is hardly formed,
thereby enabling to obtain high withstand voltage, even if the distance
between the extraction conductors is short.