PURPOSE: To provide the easy, safe and precise aligning method.

CONSTITUTION: In the aligning method of rolling mill which executes measurement from the reference face of a housing 1 by use of a jig 14, while the jig 14 is placed between blocks 3 arranged at the tip of left/right screw shafts 2 which adjust roll interval and compression force is applied between the housing 1 and jig 14, the distance between the first reference face of housing 1 and an end face of the jig 14 is measured. In the same way, the distance 2 between the reference face of housing and an end of the jig 14 opposite to the above end part is measured, by adjusting the screw shafts 2 so as to make the distance 1 and 2 equal, the distance of left/right blocks from the pass line are made equal.