A belt tensioning device for a belt drive which comprises a driving machine with a driving belt pulley drivable by a driveshaft around a driving axis, and a plurality of further belt pulleys and with an infinite belt which is wrapped around the driving belt pulley and the further belt pulleys wherein the belt tensioning device comprises a housing in which two tensioning arms are supported so as to be pivotable around a common pivot axis, in which tensioning arms there are supported tensioning rollers with axes of rotation extending parallel to the driving axis, wherein the tensioning arms are supported relative to one another by spring means, wherein, with the driving belt pulley mounted at the driving machine, the housing can be mounted in that, in an annular region surrounding the driveshaft of the driving belt pulley, the housing is contact-free relative to the driving machine.