A torsion coil spring is a spring that receives a torsion torque around a coil axis. Depending on the rotational direction of use, stainless steel wire etc. are wound clockwise or left and formed into a coil shape. A wide range of production is possible from the minimum wire diameter of 1mm or less to several tens of mm. The shape of both ends of the torsion coil spring is determined by the mounting site and mounting method, so it is characterized by various shapes. It is used for various purposes such as clip parts such as clips, parts for opening and closing mailboxes and doorknobs, and assisting in opening and closing lids.