PURPOSE: To precisely position tiles, by providing both length and breadth lines at the same position with a tile unit on which a plurality of tiles are regularly arranged and stuck and lining up the length and breadth lines to make a straight line on setting it with pressure.

CONSTITUTION: Length lines 4, 4a and breadth lines 5, 5a are lined up at the same position of the surface of a sheet material made of synthetic resin film on which a plurality of tiles are stuck, on fabricating a tile unit 7. And setting bed mortar and installing mortar are spread on the applied face 9 of a concrete body 8 and then joint mortar is applied over the whole rear face of the unit 7. And the unit 7 is stuck on the installing mortar with pressure so as to line up the breadth lines 5, 5a of respective units 7 on a straight line. And the length lines 4, 4a of the lower unit 7 and the breadth lines 5, 5a of the side units 7 are aligned to make a straight line to stick the unit 7 thereon by turns with pressure and then after curing of mortar, the sheet material is peeled off. In this way, an accurate work can be done and the setting work of tiles can be easily in a short time.