To improve the hot rolling DHCR ratio in a process to carry a continuously cast slab, etc., to a next process by selecting slabs of a pre-determined number of pieces based on the characteristic of each slab which is discharged from a casting process and temporarily placed to form an initial group, searching a slab group to minimize the value of the pre-determined evaluation function, and loading the component slabs thereof on a truck.

The characteristic value of each slab manufactured by a continuous casting machine or temporarily placed is taken in. Arbitrary N slabs are selected among the total slabs to generate a slab group comprising these selected slabs. The evaluation function and the degree of adaptability are calculated for each slab group, and the slab groups of the specified sets (M sets) are selected based on the degree of adaptability. The genetic operation is achieved to the selected slab groups to judge whether or not the condition for the slab group search operation is satisfied, and when the judgment is NO, return to the step to select the arbitrary N slabs. If the judgment is YES, select the slab group having the maximum degree of adaptability among the slab groups of M sets.