PURPOSE: To enable the reflection plate to be simply and quickly set, and surely prevent it from being left behind.

CONSTITUTION: The reflection plate installation is equipped with a spare tire carrier 12 which is assembled to a body rotatably in the horizontal direction at a place between a position where a reflection plate falls to the rear section of the body and a position where it is projected afterward from the rear section, and also detercahably mounts a spare tire 14, and with the reflection plate 13 which is assembled in the spare tire carrier 12 rotatably in the vertical direction at a place between a position where the reflection plate falls in the inner side of the spare tire carrier 12 and a position where it rises from the upper section of the spare tire carrier 12. Besides, a magnet 20 is integrally provided for the reflection plate 13, and a first magnet receiver 15 which is sucked up by the magnet 20 when the reflection plate 13 is in a falling position with respect to the spare tire carrier 12, and a second magnet receiver 21 which is sucked up by the magnet 20 when the reflection plate 13 is in a rising position, are integrally provided.