A modular rolling mill has a mill pass line along which products roll. The rolling mill comprises first gear units arranged along a first line parallel to the mill pass line. Each first gear unit is driven individually by a motor and has a pair of mechanically interconnected first shafts. Second gear units are arranged along a second line between and parallel to the first line and the mill pass line. Each second gear unit has a pair of mechanically interconnected second shafts. Rolling units are arranged along the mill pass line, which are driven by an input shaft and has a pair of roll shafts carrying work rolls. First couplings connect the first shafts of each first gear unit to second shafts of two successive gear units, and second couplings releasably connect the second shafts of the second gear units to the input shafts of two successive rolling units.