PURPOSE: To equalize the lowering speeds of plural parisons coming out of the parison with plural outlets by providing a simple structure capable of easily altering the cross sections of each flow path to the plural outlets of the parison head.

CONSTITUTION: To equalize the lowering speeds of a parison 4 to be extruded from each outlet, a filter 29 attached to the downside of a tapered part 19 is removed out, a tool of a square cross section is inserted into the central hole 28 and coupled with the squre hole 27 of a stopper 26, the stopper 26 is turned and reciprocally moved by means of the screw, and the opening of the outlet of the pipe part 25 is altered for regulation.