Abstract: Hook adapted to be easily, quickly and securely attachable on both ends of an elastic cord which is used to tie objects up is disclosed; the present hook is structured to have two symmetric round ends, i.e., the right cord-fixing end and the left hook end, with a relatively large through-hole placed on the latter and three smaller through-holes disposed on the former with one of which being cut open for ready disposition of part of the elastic cord in knotting operation, and there is also provided with a hook member projectingly extended from the left end with the concave thereof facing to the right.