A balun includes a core having a plurality of through holes and a plurality of conductors wound around a portion between two through holes in the core and constituting first and second coils. The conductors include parallel lines in which a first conductor, a second conductor, and a third conductor are arranged in substantially parallel in this order and are integrated so as to include planar sections. The first and second coils include a continuous portion of first, second, and third winding portions. The first winding portion is formed of the wound second conductor. The second winding portion is formed of the parallel lines wound such that the planar sections cover the first winding portion. The third winding portion is formed of the second conductor wound on the second winding portion. The first coil includes a center tap connected to end portions of the first and third conductors.