An apparatus for tensioning a band, in particular a strapping device, includes a drive unit (10) which, in the operated state, drives a band winding unit (12) selectively in opposite directions of rotation. As a result of the band (18), which can be inserted into the apparatus, being releasably locked in predefinable positions by an operating device (14) actuated by a control device (16) of the band winding unit (12), functional positioning of the band winding unit is started to fix the band. The band can be inserted into the apparatus, in the tensioned or tautened state to then be able to insert the band tensioning apparatus for a new strapping operation after the band is severed.