Abstract: A mechanical device was invented for prestressing of carbon fiber reinforced polymer (CFRP) sheets. Significant features of this device are that the CFRP sheets are directly anchored to the mechanical device itself, the prestressing forces are applied with a manual torque wrench without the need for power operated hydraulic jacks and the prestressing transfer is accomplished under slow strain rates. Experimental investigation clearly indicates that the device was efficient in applying prestressing to the CFRP sheets and prestress losses during stressing were maintained at a minimum.