A constructive arrangement applied to swivel castor guards represented as an improvement that provides the possibility to interchange an infinite variety of end pieces on a single basic castor structure, providing the ability to create a wide range of castor models at a reduced cost, considering that the constructive arrangement disclosed requires a reduced amount of investment in production tooling, limited to the interchangeable end piece, as the new components, namely the main body with a wheel guard having a slot on its trailing end face and the intermediate part, which are part of the improvement, can be considered as standard parts.