A method for manufacturing a coil device comprises a first step of twisting a tip end part of the conductive wire by approximately 90 degrees with respect to a conductive wire portion arranged rearward continuously from the tip end part to form a twist part, and winding the tip end part of the conductive wire around the outer peripheral surface of the core in a lying posture on the outer peripheral surface; a second step of winding the conductive wire arranged rearward continuously from the twist part around the outer periphery surface of the core in a standing posture on the outer peripheral surface; and a third step of transforming the conductive wire on a tip end side with respect to the twist part in a direction apart from the outer periphery surface of the core to form one lead part extending substantially linearly.