Hair bundling core and method of using the core

A method of using a hair bundling core structure, which includes an elastic cylinder made of a foamed synthetic resin having a thickness and strength which are sufficient for facilitating a piercing of a hair setting U-shaped pin having pair of legs into and an extraction of the U-shaped pin from the elastic cylinder and for fixing hair to the elastic cylinder by the piercing of the U-shape pin, said elastic cylinder having a pair of end surfaces and is cut from one end surface to the other end surface to form a rift, said method comprising steps of:

• setting hairs in a preset range of a head of a user into a first hair bundle having a root portion which is defined by a mass of root neighboring portions of the hairs, and binding a lower end of said first hair bundle in the root portion at a center of said preset range near roots of the hairs;
• pinching the root portion at two sides of said center of the preset range with a pair of hairpins;
• opening said rift to form a gap and inserting a lower portion of the root-bound, first hair bundle through the gap into a hole of the elastic cylinder to let the lower portion pass through the hole;
• pushing said core structure at its lower face onto an outer face of the head within said preset range;
• and
• fixing said core structure on the head of the user with said U-shaped pin by inserting one of the legs between said hairpins and a head skin, while said core structure is being pushed, and by piercing the other leg into a lower part of said core structure so that said core structure may be provided as a hair setting base.