The coil device comprises the magnetic core comprising the axial part and the magnetic core end part connecting to the axial part, the coil part formed by winding the wire around the axial part, and the electrode part provided at the magnetic core end part and made of good conductor. Said electrode part comprises the fixing surface fixed with a wire end part of said wire, and the fixing surface is provided on a side surface which does not intersect with a center axis of said coil part at said magnetic core end part. Said fixing surface is inclined to a direction away from said center axis with respect to a direction towards said magnetic core end part from said axial part.