Provided is a road traffic-control signboard assembly with which a road traffic-control signboard can be assembled while being linked with a vertical support at right angle. The road traffic-control signboard assembly is fitted with and fixed to a road traffic-control signboard stay bar and has a structure of being returned to an original position even if impact by typhoon or collision of vehicles is applied to the road traffic-control signboard. Thus, the road traffic-control signboard assembly prevents a phenomenon that an initial fixed position of the road traffic-control signboard is changed because of impact by typhoon or collision of vehicles which is applied to the road traffic-control signboard, to thereby lose the function of the road traffic-control signboard.