In a linear guide unit that has an elongated guide housing which limits a guide hollow space with a longitudinal opening, a wagon arrangement which is displaceably guided in the guide hollow space on guide rails, a connection part for connecting the wagon arrangement to an object to be guided, a cover element arranged between movement tracks of the connection part and covering the longitudinal opening, in accordance with the present invention forwardly of and/or rearwardly of the wagon arrangement, at least one support unit is arranged displaceably in direction of the longitudinal axis for supporting the cover element relative to the guide housing; also additionally or alternatively the support unit can support the cover element relative to the wagon arrangement.