PURPOSE: To prevent the burning of a straightening roll of a H-shape steel and a guide roll without a slip, etc., and to drastically reduce the wear of the roll in the roller straightening of the H-shape steel.

CONSTITUTION: A lubricant composition containing 20 to 70weight% high basic metal sulfonate in lubrication base oil based on the total weight of the composition is directly or indirectly supplied to the side surface of the straightening roll 2, the inner surface of the flange of a H-shape steel 4 to be straightened by the roll 2, a guide roll and the outside surface of the flange of the H-shape steel subject to the friction of the guide roll.