Described is an apparatus for the production of transversely ribbed tubes comprising mold jaw halves which are movable in a condition of bearing against each other along two guide. The guide paths have a common mold section, a respective return section and two respective direction-changing sections. The respective direction-changing section has a direction-changing member which is linearly movably guidedly arranged on a base element fixed with respect to the machine and which is connected to a compensating device which is provided to compensate for the tolerance play of the mold jaw halves which circulate along the associated guide path, said tolerance play being dependent on the temperature and/or the speed of the mold jaw halves.