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 (D), - a first holding device , the first holding device comprising at least a first and a second guide wheels , the first and second guide wheels 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 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 with the respective first and second rolling tracks 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 (D) of the motorized drive device along the rail , so as to insert or extract the first and second guide wheels 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 (D), - a first holding device , the first holding device comprising at least a first and a second guide wheels , the first and second guide wheels 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 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 with the respective first and second rolling tracks 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 (D) of the motorized drive device along the rail , so as to insert or extract the first and second guide wheels into or from the rail , through the slot of the rail . <EOS>