Improved device for the supply of fibers to a filling machine of a brush manufacturing machine of the type which mainly consists in a drawer (4) movable between a fixed multiple fiber container (1) and a pick-up device (5), in which this drawer (4) consists in a number of relatively small loading spaces (2,3), which act as locks for the moving of the fibers (6, 7, 14, 15) out of the fiber channels (8, 9) of aforementioned fiber container (1) to the cluster pick-up device (5), characterized in that the loading spaces (2, 3) are of such shape that regardless of their position a connection remains with the subject fiber channel (8), respectively (9).