To execute additional cooling without interrupting the continuity of a drive array by providing gaps on a rolling sequence for a module type rolling mill.

In this module type rolling mill, gear units GU1, GU2 are installed between selected rolling units in place of the rolling units RU2, RU4 which are removed from a rolling route line PL to provide gaps in the rolling sequence. Each gear unit GU1, GU2 is connected to drive units DU1-DU4 which are formerly connected respective removed rolling units and composed so as to operate the next succeeding rolling units at the speed of the respective removed dummy rolling units by providing the continuity to the drive train for the rolling mill. The gear units have a water box or other equivalent cooling device which acts so as to lower the temp. of a product between continuous roll routes.