Abstract: In repairing lining damage in a blast furnace, the furnace is blown down after lowering the burden inside to below the damaged part. Then a plurality of openings and a refractories filling aperture are provided through the furnace wall in the damaged part. A preliminarily prepared panel is lowered down through an opening in the furnace top to a position opposite to the damaged part. One end of a string-like member whose other end is fastened to the panel is drawn outside the furnace through one of the openings. The whole length of the string-like member is protectively covered by a single or double support tube and stretched therethrough. Monolithic refractories are forced in through the refractories filling aperture into a clearance between the damaged part and panel either during blowing down or after blowing in.