In a coil component, a double coil is configured of a first coil portion and a second coil portion, and a first through conductor of the first coil portion and a second through conductor of the second coil portion are adjacent to each other. Thus, the first coil portion and the second coil portion have enhanced magnetic coupling at locations (that is, the first through conductor and the second through conductor) at which planar coil patterns of upper and lower surfaces of an insulating substrate are connected, in addition to magnetic coupling in the planar coil patterns wound around a through hole. Therefore, according to the coil component, a high coupling coefficient between the first coil portion and the second coil portion is realized.