To easily change-over the movement/restraint states of a supported object by providing temporary holding mechanism which temporarily holds a movement support body to a movement position against the weight of the supported object such as furniture, etc., and moves the movement support body to a saving position where a restraint support body is functioned when more weight is loaded.

When the support end 7a of a caster 7 is in a project position B, it is projected to a floor surface F side from the support end 6a of an adjuster 6 so that the support end 7a is abutted on a floor surface F and the caster 7 is held to the project position B by temporary holding mechanism 8. That is, a foldable table is kept in a movement possible state. In the meantime, when a hand is put on the top plate of the foldable table, etc., and loading on the foldable table is increased, a ball 81 is separated from the recessed part 82 of a shaft part 61 and the temporary holding state is released. That is, the ball 81 is moved to ball containing space S, the caster 7 is set in a saving position direction and the support end 6a of the adjuster 6 is abutted on the floor surface F so that the restraint state is established.