This invention relates to a rolling mill apparatus and a method of shape control of a rolled strip which enables satisfactory shape control even in extremely thin rolling. A rolling mill apparatus of this invention has a rolling mill, which rolls a rolled strip P between upper and lower work rolls; a shape detecting portion, which detects the degree of flatness of the rolled strip in the width direction of rolled strip which has been rolled by the rolling mill; a spray portion, having a plurality of spray nozzles arranged along the length direction of the upper and lower work rolls, which sprays the upper and lower work rolls with coolant C; and, a shape control portion, which adjusts the spray amount and/or temperature of the coolant C sprayed from the spray portion based on detected information from the shape detecting portion, to control the shape of the rolled strip P. The shape control portion has two control modes, in which the relationship of the detected information of the shape detecting portion and the spray amount and/or temperature of the coolant C sprayed from the spray portion are inversely proportional, and switches between these two control modes based on the strip thickness of the rolled strip P.