PURPOSE: To prevent the generation of fish tails and broadside tinning-down in the end parts of slabs in the stage of middle rolling of continuously cast slabs with hot strip mills having a vertical scale breaker by subjecting the end parts of the slabs to broadside screwing down with the vertical rolls which are held stopped.

CONSTITUTION: In the stage of producing hot strips of various widths from a continuously cast slab of a specified width, the slab is subjected to descaling and rolling for the purpose of width adjustment with vertical rolls of vertical rolling mills. Here, fishtails of a recessing shape and the parts of a narrow width are usually produced in the preceding and succeeding ends of the slab, and are required to be cut away before the slab is fed to finishing mills, due to which the yield of the material is decreased considerably. To prevent such decrease, in the stage of broadside rolling of the slab with the vertical rolls, broadside screwing-down is applied to the end parts of the slab with the vertical rolls which are held stopped, whereby the preceding and succeeding ends of the slabs are formed to the sections of a dogbone shape similar to the shape in the central part. There is no need for cutting the preceding and succeeding end parts of the slab, and the slab is rolled to a hot strip in higher yields.