A mobile lifting device comprises a mobile frame (1, 12, 13) with a set of lift forks (3) for receiving a pallet thereon. The pallet truck is provided with a weighing device which comprises at least one pressure or strain-sensitive sensor (20) in addition to a display panel (21) for indicating thereon a value measured by the sensor. The sensor is connected firmly to a pan (12) of the frame and able to determine a mechanical deformation in that part of the frame. The weighing device comprises this sensor.