PURPOSE: To avoid provision of a dead part on an advertising surface and to decrease the tensile force in the fixing part of a sheet.

CONSTITUTION: The sheet 6 to constitute a signboard surface is turned back from a signboard frame 2 fixed along the edge of the aperture of a signboard housing 1 and is fixed by means of a hook bolt 5 via a fixture 8 inserted into bag-shaped parts 7 formed at both ends of the sheet 6. Since the sheet 6 is turned back and mounted on the signboard frame 2, the tension generated in the sheet part of the signboard surface is decreased by the friction force generated in the turn back part of the signboard frame 2 and is transferred to a sheet fixing part. The tensile force of the sheet fixing part is decreased and the safety in structural strength is enhanced.