PURPOSE: To reduce occupying space of the whole apparatus by fitting a piston in a cylinder part, driving as advancing/retreating with fluid pressure, extending a piston rod to die direction from the piston and inserting/taking out top part of a feeder head rod into/from cavity in the die with advance/retreat thereof.

CONSTITUTION: In the feeder head rod device 20 attached to an injection forming apparatus, the cylinder part 21 connecting each end face of both sides with inner face of a die fitting plate 5 housed in a recessed hole 6a, which has bottom and cylindrical shape and is arranged as opening to the other member side in either one of the die 6 or the die fitting plate 5, and bottom face of the recessed hole 6a, respectively, is arranged. The piston 22 is fitted to inner hole in the cylinder part 21. The piston rod 24 is extended to the piston 22 and the feeder head rod 29 inserted into/taken out from the cavity 13, is fitted to this. By this method, the feeder head rod device can be compactly constituted in the small size.