The invention relates to a mobile strapping device for strapping packed goods using a strap, said device comprising a tightening mechanism for applying tension to a loop of a strap, a friction welding element (5) for producing a friction welding connection for two overlapping regions of the loops of the strap, and a rechargeable energy accumulator (10) for storing energy, especially mechanical, elastic or potential energy that can be released as drive energy for the friction welding element (5) for producing a friction welding connection. Such a mobile strapping device can be used without a battery, with the highest level of efficiency. To this end, the energy accumulator (10) can be charged by means of a manually actuatable actuating element, and when energy stored in the energy accumulator (10) is released therefrom, a movement is carried out without reversing the direction of the movement.