PURPOSE: To dispense with a working scaffold at the time of painting so as to reduce cost and to shorten a construction period by providing a circumferential rail at a supporting beam provided at a supporting tower, providing this circumferential rail with a moving rail in a travelable state, and suspending a working floor from the moving rail elevatingly through a hoist part.

CONSTITUTION: A working floor 6 is first lowered to the ground, and after workers and necessary painting equipment and materials are mounted on the working floor 6, the hoisting device of a hoist part 5 is driven to move up the working floor 6. When the working floor 6 reaches an uppermost part, a motor-driven trolley part 5b is driven to make the hoist part 5 travel along the rail (a) of a moving rail 4 onto a supporting tower B1 side, thus moving the working floor 6 to the supporting tower B1 side. When the working floor 6 gets very close to the top part at the supporting tower, the movement of the hoist part 5 is stopped, and after performing the painting work of an area that can be performed within the working floor 6, a travel part 4b is driven to move the moving rail 4 along a circumferential rail.