Piece and operating method thereof

PURPOSE: A hair extension being easily attached and an attaching method thereof are provided to easily not being cut although hair extension is pulled down and reduce required time to be attached. CONSTITUTION: An attaching method for hair extension comprises; a step which inserts the body(21) of a crochet hook(20) into the end of a thread(11), a step in which the end of the thread end is hung on the body of the crochet hook, a step which places the thread in the inner side of a hook(22) by opening the hinge pin(23) of the crochet hook, a step which forms a first knot by moving the end of the thread to hook in the state that the hinge pin is closed and the hook is closed, a step which moves the first knot to the body by opening the hinge pin, a step which closes the hook by closing the hinge pin after placing real hair in the inner side of the hook, a step which frees the real hair from the inner side of the first knot with a ring type by getting out the crochet hook from the first knot, and a step which forms a second knot in the real hair by getting the end part of the real hair from the ring of the real hair.