To fold a fly cloth with no drift against a weave texture or a pattern by mounting the fly cloth on a fly cloth mounting bed in the adsorbed state, pressing the fly cloth with a presser plate, advancing folding pieces to fold both sides of the fly cloth, and pressing a steam pressboard from above for steam pressing.

A suction source 2 is operated before work, and a fly cloth and a core cloth are correctly mounted on a fly cloth mounting bed 3 along a laser beam. A presser plate 4 is lowered to press the center section of the fly cloth on the fly cloth mounting bed 3. Both sides of the fly cloth are somewhat lifted, and folding pieces 5, 5 are advanced to fold both sides of the fly cloth. A steam pressboard 6 is lowered to the position near the upper faces of the folding pieces 5, 5, and the folded portions of the fly cloth are pressed from above not to beretumed to the original positions. The folding pieces 5, 5 are retreated, the steam pressboard 6 is lowered, and a steam valve 12 is opened for steam pressing.