The present invention relates to an improvement in caster swivel restriction structure. The present invention is characterized in that a swivel brake plate has a body piece having a plurality of through holes arranged therein and latch pieces bent downward from the body piece, a support base has latch hole portions for fitting the latch pieces in a vertical slidable manner, a gap portion provided at a location corresponding to below the group of through holes formed in the swivel brake plate, and cushioning members or biasing members which are disposed in the gap portion and supports the swivel brake plate aloft and which is repulsively compressed when downward force is applied to the swivel brake plate.