Coil device

A coil device comprising:

• a core having a columnar portion extending in a predetermined extending direction;
• a first coil including a plate-shaped first coil body having a first end and a second end, the first coil body being spirally wound on the columnar portion of the core along the extending direction such that the second end is positioned on one side in the extending direction relative to the first end;
• and
• a second coil including a plate-shaped second coil body having a third end and a fourth end, the second coil body being spirally wound on the columnar portion of the core along the extending direction such that the third end is positioned on the one side in the extending direction relative to the second end of the first coil, and the fourth end is positioned on the one side of the extending direction relative to the third end, the second coil being in electrically parallel connection with the first coil.