A belt pulley device (12) is adapted to be mounted on a garden tractor for rotating, together with a horizontal first belt pulley (5) and an endless V- belt (8), a substantially horizontal second belt pulley (9) for driving of an im¬ plement mounted on the front of the tractor. The first belt pulley (5) is located at a higher level than the second belt pulley (9). The belt pulley device (12) is adapted to guide one run (8a) of the V-belt (8) that runs out from the first belt pulley (5) from the higher level down to the lower level and to guide the other run (8b) of the V-belt (8) that arrives at the first belt pulley, from the lower level up to the higher level. The belt pulley device (12) has a frame (13), which is adapted to be attached to the tractor and which supports two guide belt pulleys (21 a, 21 b), which, with the frame attached to the tractor, are tilted in such a manner relative to a vertical plane parallel to the longitudinal direction of the tractor that they form together an upwardly open V-shape, and are located slightly behind the first belt pulley (5) with their upper portion being on a level therewith and with their lower portion being on a level with the second belt pulley (9). A garden tractor is provided with a belt pulley device of this kind.Linvention concerne un dispositif de poulie à courroie (12) qui est adapté pour être monté sur un tracteur de jardin pour faire tourner, conjointement avec une première poulie à courroie horizontale (5) et une courroie trapézoïdale sans fin (8), une seconde poulie à courroie sensiblement horizontale (9) pour un entraînement dun instrument monté sur lavant du tracteur. La première poulie à courroie (5) est située à un niveau supérieur à celui de la seconde poulie à courroie (9). Le dispositif de poulie à courroie (12) est adapté pour guider un brin (8a) de la courroie trapézoïdale (8) qui sétend depuis la première poulie à courroie (5) du niveau supérieur jusquau niveau inférieur et pour guider lautre brin
