Abstract: In a coil device (1) which has a plurality of winding drums (6) on a bobbin (2) with a partition (5) formed between flanges (3), (4) at both ends of the bobbin, the partition (5) has a slit (7) through which a wire (w) is passed, and among winding pitches of the wire wound on adjacent winding drums (6) with the partition (5) therebetween, at least a pitch (P1) between a segment of the wire passing through the slit and its adjacent segment of the wire is larger than a pitch (P2) between the segments of the wire at other portions. The positions of the slit (7) of the partition (5) and a slit (8) of the flange (3) are displaced by a predetermined angle with respect to the center of the winding so to angle the wire passing through both slits with respect to the center of the winding. And, the coil system (1) has a one-side radiused portion (7b) formed at the slit end with which the wire passing through the slit (7) of the partition (5) is slidably contact.