PURPOSE: To safely replace a display board by arranging a pair of vertical frames standingly provided on both the sides of the doorway of a car, and lateral frames installed between the top parts of the pair of vertical frames, to screw the display board for displaying respective floors to the lateral frames.

CONSTITUTION: Respective stage parts 1a and 2a are formed on the top parts of a pair of vertical frames 1 and 2, and the lateral frame 4 are formed on the stage parts 1a and 2a to be laterally installed between the top parts of the frames 1 and 2. The frames 4 are fixed to the supporting pieces 1b and 2b of the frames 1 and 2 by a bolt 6, and are fitted with a stainless steel made cross section in approx. L-shape as a whole. The board 12 is constituted of a bottom surface part 13, a front surface part 14, and floow display boards 18 respectively, to be fixed to the bottom surface part 5 of the frames 4 by dish acrews 25. When replacing respective floor display boards 18, the boards 18 can be dismounted from a lateral by loosening and dismounting the screws 25 to pull the board 12 downward.