To enhance the productivity of a tiled building panel.

A plate-shaped water-containing mat 15a is formed by dehydrating a molding material slurry based on cement and fibers by a casting method or a papermaking method and a tile sheet 18 is formed by bonding a plastic film 20 or pasteboard to the surfaces of a large number of preliminarily arranged tiles 19 to be superposed on the water-containing mat 15 so that the plastic film 20 or pasteboard becomes an upper side. In this state, the superposed one is pressed through an elastic sheet 22 by a press plate 17 while the water- containing mat 15a is dehydrated from the uneder surface thereof under reduced pressure by a vacuum dehydration box 14 to bond the tiles 19 to the water- containing mat 15a under pressure. At this time, the elastic sheet 22 expands into joint parts 23 by press pressure to seal the joint parts 23 and plays an important role in the molding of the molding material built up within the joint parts 23 from below.