A mobile enclosed space, preferably a caravan, sales and/or exhibition trailer, motor home or container, - including a base module which defines a base space, said base module comprising a floor plate, frontal side walls (28, 29), and a roof, - including at least one hinge wall which is associated with said mobile enclosed space, comprises an expansion floor plate, and may be folded down, and - including at least one expansion space element which comprises a roof, frontal side walls (28, 29), and a longitudinal face, and which, when in a use position and in conjunction with the folded-down hinge wall, forms an expansion space extending the base space, - wherein a guide mechanism consisting of rollers and running rails is provided between the expansion space element and the hinge wall for sliding the expansion space element onto the hinge wall when the latter is in its folded-down condition, - wherein the guide mechanism has at least one guide carriage including rollers (46, 48), and - wherein the guide mechanism comprises running rails (41, 43) which have a first guide portion on which the rollers having a horizontal axis may roll and a second guide portion along which rollers having a vertical axis are guided, and wherein the movement of displacement of said at least one guide carriage is oriented with respect to the first guide portion, characterised in that - the guide carriage has a main body on which a fastening portion is provided, followed by a U-shaped profile, and - at least two rollers are rotatably mounted around horizontal axes provided opposite to the fastening portion on the main body, and at least two rollers are rotatably mounted around vertical axes provided on attaching straps of the main body. - including a base module which defines a base space, said base module comprising a floor plate, frontal side walls (28, 29), and a roof, - including at least one hinge wall which is associated with said mobile enclosed space, comprises an expansion floor plate, and may be folded down, and - including at least one expansion space element which comprises a roof, frontal side walls (28, 29), and a longitudinal face, and which, when in a use position and in conjunction with the folded-down hinge wall, forms an expansion space extending the base space, - wherein a guide mechanism consisting of rollers and running rails is provided between the expansion space element and the hinge wall for sliding the expansion space element onto the hinge wall when the latter is in its folded-down condition, - wherein the guide mechanism has at least one guide carriage including rollers (46, 48), and - wherein the guide mechanism comprises running rails (41, 43) which have a first guide portion on which the rollers having a horizontal axis may roll and a second guide portion along which rollers having a vertical axis are guided, and wherein the movement of displacement of said at least one guide carriage is oriented with respect to the first guide portion, characterised in that - the guide carriage has a main body on which a fastening portion is provided, followed by a U-shaped profile, and - at least two rollers are rotatably mounted around horizontal axes provided opposite to the fastening portion on the main body, and at least two rollers are rotatably mounted around vertical axes provided on attaching straps of the main body.