Abstract: A holding device installable on a motorcycle for supporting saddlebags, lateral baggage pouches or luggage pieces is made of a strong, fracture-resistant synthetic material and includes two lateral holding frames which support upper frames interconnected by a transverse luggage rack. The rear part of the lower side of the upper frames has an extension for supporting transverse fastening screws which are guided in grooves formed in the top side of the underlying holding frame. The upper guiding groove permits the tilting of the upper frames downwardly about a quadrant. At the front end of the lower side of the upper frame is formed a locking nose engageable in a corresponding recessed receptacle in a lateral wall of the top side of the holding frame. By displacing and tilting the holding device, it is possible to swing open the seat of the motorcycle to access a storage compartment below the seat.