PC support adaptable to motor-vehicle seats

The device has a rigid reinforcement (5) removably fixed to a front face of a backrest (2) of a seat (1) by a lower strap (6). A support assembly supports a plate (33) to receive a laptop, and comprises a support arm (12) having an end connected pivotally to the reinforcement. A plate support foot forming portion (32) is rotatably mounted and slidably guided on the support arm, and lockable on the arm by a locking unit in a preset relative position. The support foot forming portion comprises a cylindrical supporting column (34) with an end carrying the plate.