PURPOSE: To provide a synthetic resin net manufacturing device wherein cut surface is flat, operation is easy and manufacturing is simple.

CONSTITUTION: In a synthetic resin net manufacturing device wherein resin extruded through an extruding machine 1 is led to a net molding die, netlike cylinder 8 is made, the cylinder 8 is cooled and cut and a platelike net is prepared, a branch pipe 4 is provided in a resin passage extending to the upstream side of a die from the downstream side of the extruding machine 1, a flow adjusting valve 5 is provided in the branch pipe and joined to an extruding die 6 of a beltlike body. Then the extruding die 6 is provided in the vicinity of the netlike cylinder 8 extruded to the upstream side of a cooling water tank 7 and a cutting device 10 for cutting off the netlike cylinder 8, to which the beltlike body is welded, at its beltlike body is provided on the downstream side of the cooling water tank 7.