The present invention relates to a mould (1) for casting molten metal into a strand with a circular or polygonal cross section in a continuous casting machine. The object of the invention is to provide a mould with which on the one hand a sufficiently strong casting taper of the mould cavity can be preset, so that an adequate and homogeneous growth of the strand shell is also ensured along the entire circumference of the casting cross section of the mould cavity, and on the other hand unnecessarily high contact pressures and frictional forces of the strand in the mould are reliably prevented, in particular jamming of the strand is reliably prevented. This object is achieved by a mould (1) in which a depression (10) or a recurring sequence comprising a region with a depression and a region without a depression extends over the longitudinal extent of the region of load relief (8) in the direction of withdrawal, wherein the depression (10) or the recurring sequence has the form of a helical line.