The elastic cord tensioning and length adjusting apparatus is designed to allow the user to have much more flexibility with a single length elastic cord, rather than using a number of cords of different lengths. The apparatus can adjust, both the tension and length of elastic cords, by allowing the user to loop different lengths of the cord in a mechanism that can lock the looped section of elastic cord so that the length of the cord not in the loop is shortened and the tension is increased. The apparatus comprises a main horizontal body having two apertures designed for the cord to pass through. A locking mechanism fits into a center aperture in the main horizontal body and has two end notches to allow the elastic cord to fit into those notches. A spring tensioning device and a retaining piece maintain the lock in position.