PURPOSE: To permit an external force exerted on a crossing gate to escape by rotating motion thereof by mounting on a supporting post a cylindrical body composed of upper and lower cylindrical members having slant edges and fixing the lower cylindrical member on the supporting post while the upper cylindrical member equipped with the crossing gate is rotatably mounted thereon.

CONSTITUTION: A cylindrical body being composed of upper and lower cylindrical members is rotatably mounted around a supporting post 1 on a road. The lower cylindrical member is formed as a retainer 6 for a crossing gate and has an upper slant edge which mates with a lower slant edge of the upper cylindrical member formed as a slidable member 7. The retainer 6 and the slidable member 7 are rotatably engaged relative to each other. The crossing gate 5 is fixedly retained by a fastening means on the outside portion of the slidable member 7 while the retainer 6 is fixed onto the supporting post 1. This construction allows the crossing gate 5 to be rotated together with the slibable member around the supporting post 1 upon collision of vehicles thereagainst so that a collision energy can be efficiently absorbed.