To improve working efficiency while positional accuracy of a net for reinforcement is ensured by a method wherein only the top ends of a pair of set rods are fitted on a set frame and after a net for reinforcement is set between the set rods, this is rotated by pinching this by means of a grasping tool from the top and it is taken out with the set frame and is set on a form.

A set frame 4 fitted with set rods 2 and 2 is lowered by means of a crane on nets 3 for reinforcement arranged between blades 6 and 6 of an arranging tool 5 to place the net 3 for reinforcement between the set rods 2 and 2. Then, from a grasping tool inserting hole between rows of the set rods being arranged transversely on one row, a grasping tool 7 supported freely rotatably by the upper supporting plate 8 is lowered and the net 3 for reinforcement is inserted into a forked slit on the apex. Thereafter, the grasping tool 7 is rotated by 90° by a rotating means to grasp the net 3 for reinforcement so as to twist it and to grasp it by utilizing the deformation of the net and it is transferred on a form for casting of mortar. This grasping tool has a function for preventing the net for reinforcement from floating up to ensure the positional accuracy.