PURPOSE: To simplify the fitting work of a panel/and upgrade the appearance.

CONSTITUTION: On the peripheral parts of respective panels 5, 6, bent parts 7 are formed, and on the side peripheries of the respective panels 5, 6, a plurality of engaging parts 8, 9 that have been bent toward the outside of the panel are provided respectively. The engaging parts 8 of the panel 5 are provided in the positions opposite to the engaging parts 9 of the panel 6, and on the longitudinal furring strips 11 a plurality of projections 12 directed upward and capable of alternately inserting the engaging parts 8, 9 of the panels 5, 6 are provided. The longitudinal furring strips 11 are fixed to a wall surface or to lateral furring strips.