Abstract: A tensioning device for a chain or a belt drive for a motor of a hand machine tool, especially for a chain saw or a grinding or abrasive cutting-off machine, with a longitudinally movable bracket, such as a bracing or an arm, which can be fixed together with a cover with at least one bolt with a screwable nut to a casing or to another part of the hand machine tool, whereby the tensioning device has an adjusting screw extending in the longitudinal direction of the bracket on which a rider screw is movable to-and-fro by rotating the adjusting screw, the rider screw having a trunnion extending through an opening of the bracket so that, for tensioning the chain or the belt drive, the bracket follows a movement of the rider screw.