To solve the problem of an abrasion loss of the part and increased consumption of energy when an injection material supplied under high pressure receives resistance by acute angle bending of a flow passage since the flow passage formed of a terminal of an injection material supply passage and a nozzle structure part inflow port succeeding to this terminal conventionally bends at an acute angle in a state being close to a right angle.

A connecting flow passage of the terminal 23 of the injection material supply passage of an injection rod and the nozzle structure part inflow port 24 of an injection nozzle, is constituted in a curved gradient, and is also constituted so as to connect the terminal of the injection material supply passage and the nozzle structure part inflow port of the injection nozzle by an attachable-detachable flexible pressure hose 5.