A motorized drive device of an occultation or solar protection device, the motorized drive device being provided for moving at least one screen along a rail of the occultation or solar protection device according to a sliding movement, the motorized drive device comprising at least: - an electric motor, - a drive wheel, the drive wheel being configured to be rotated by means of the electric motor and to be brought into contact with at least one running surface of the rail, so as to move the motorized drive device along the rail in a direction of movement, - a first holding device, the first holding device comprising at least a first and a second guide wheels (38a, 38b), the first and second guide wheels (38a, 38b) being configured to be inserted into or extracted from the rail, through a slot of the rail, and to be brought into contact with at least a respective first and a second rolling tracks (8a, 8b) of the rail, so as to hold or release the motorized drive device relative to the rail, and - a first switching mechanism, the first switching mechanism being configured to drive at least the first guide wheel of the first holding device between a first position and a second position, and vice versa, characterized in that, in a first position of the first switching mechanism, the first guide wheel of the first holding device is offset relative to the second guide wheel of the first holding device, so as to hold the motorized drive device relative to the rail by supporting first and second guide wheels (38a, 38b) with the respective first and second rolling tracks (8a, 8b) of the rail, and in that, in a second position of the first switching mechanism, the first guide wheel of the first holding device is positioned opposite the second guide wheel of the first holding device, in the direction of movement of the motorized drive device along the rail, so as to insert or extract the first and second guide wheels (38a, 38b) into or from the rail, through the slot of the rail. - an electric motor, - a drive wheel, the drive wheel being configured to be rotated by means of the electric motor and to be brought into contact with at least one running surface of the rail, so as to move the motorized drive device along the rail in a direction of movement, - a first holding device, the first holding device comprising at least a first and a second guide wheels (38a, 38b), the first and second guide wheels (38a, 38b) being configured to be inserted into or extracted from the rail, through a slot of the rail, and to be brought into contact with at least a respective first and a second rolling tracks (8a, 8b) of the rail, so as to hold or release the motorized drive device relative to the rail, and - a first switching mechanism, the first switching mechanism being configured to drive at least the first guide wheel of the first holding device between a first position and a second position, and vice versa, characterized in that, in a first position of the first switching mechanism, the first guide wheel of the first holding device is offset relative to the second guide wheel of the first holding device, so as to hold the motorized drive device relative to the rail by supporting first and second guide wheels (38a, 38b) with the respective first and second rolling tracks (8a, 8b) of the rail, and in that, in a second position of the first switching mechanism, the first guide wheel of the first holding device is positioned opposite the second guide wheel of the first holding device, in the direction of movement of the motorized drive device along the rail, so as to insert or extract the first and second guide wheels (38a, 38b) into or from the rail, through the slot of the rail.