bent portion of the upper hook 1 and be further drawn in a bent state step g when the warp 8 is thus pulled backward and the weft 10 passes through the loops of both warp 8 and weft 10 already formed on the bent portion of the upper hook 1 said hook 1 is inclined to release the knot jointly formed by both warp 8 and weft 10 from said bent portion later the upper hook 1 makes half a rotation to the right or left back to its original position shown in step a the knot formed on the net cord through the above mentioned steps a to g is presented in fig3 a fig3 b illustrates the largely loosened state of said knot there will now be described still another embodiment of this invention with reference to fig4 a to 4g showing the sequential steps a to g of forming a knot step a this is the initial step of forming a knot showing the regular positions of the warp 8 weft 10 and the components of a net manufacturing machine step b while the upper hook 1 makes half a rotation to the right the weft lifting plate 5 is brought upward to catch the weft 10 step c when the upper hook 1 further makes half a rotation to the right after holding the weft 10 the weft lifting plate 5 descends step d when the upper hook 1 further makes a full rotation to the right the reed 7 rises step e the reed 7 further rises to throw the warp 8 about the bent portion of the upper hook 1 from the front side to the back side and thereafter is brought downward step f when the upper hook.