Abstract: Apparatus for the production and proper calibration of improved flexible hoses made by a soft thermoplastic material reinforced with a continuous spiral of rigid thermoplastic material. During their production the hoses do not rotate but are produced linearly and in their internal surface no longitudinal grooves are engraved. The melted coaxial materials are discharged through a rotating mechanism to a calibration unit which rotates with it and bears peripherally special inclined rollers on which is transmitted, via an epicyclic gearing system, a controlled rotation opposite to the above direction. On this calibration unit the plastic hose is formed successively, advancing linearly forward.