PURPOSE: To obtain the title low cost product having proper strength depending upon purpose of use of net fabric, readily producible, by making a reinforcing net mesh line comprising two net fabric constituent yarns at a given part of the whole net fabric by a specific method.

CONSTITUTION: The objective product which is knotless net of through type prepared by twisting strands attached to a pair of spindles and forming net legs, wherein the nets legs are advanced in plural sections divided by a reinforcing zone A, these net legs 1-5 are superimposed on one or more of net legs 6-9 of an adjoining section in the reinforcing zone A to form reinforcing net mesh line comprising two net fabric constituent yarns. To be concrete, for example, the net leg 1 is advanced zigzag between left edge part of the reinforcing zone A and right edge of the net, the net leg 6 is progressed downward to the right opposingly to the net leg 1, the net leg 1 of three legs are superimposed between the left edge part and the right edge part of the reinforcing zone A and further these operations are repeated to form reinforcing net mesh line.