An injection head for an apparatus for the production of twin-wall pipes has an external melt channel leading to an external nozzle and an internal melt channel leading to an internal nozzle. From the internal melt channel, a conically expanding internal nozzle channel leads to an internal nozzle outlet of the internal nozzle. In the region of the internal nozzle channel, an internal nozzle adjustment device is arranged by means of which the gap cross-section of the internal nozzle channel is displaceable and adjustable up to the internal nozzle outlet by radial displacement.