To provide a storage dedicated for a slope plate near an entrance in a side of a car in which a slide door opens and closes.

A foldable slope plate 1 is linearly elongated and hanged between an entrance G in a side of a car, where a slide door D opens and closes, and the ground E when in use, and is folded in half and stored upright when not in use. The slope plate 1 is provided such that the slope plate 1 can be slid through an opening D2, provided on a front end face D1 of the slide door D in a width direction of the slope plate 1, into and out of the slide door D.