A device for cleaning a bale forming roller of a round baler, particularly for round balers of the type comprising a first half-shell and a second half-shell (2a, 2b), which are articulated to each other and form internally a chamber for compressing the material to be pressed into the round bale (R); the device comprises a transverse supporting element (12), which is rigidly coupled to fixed parts of the round baler and on which a plurality of contoured teeth (13) are distributed, the teeth being mutually aligned and being able to engage in respective circumferential interspaces (11) formed on the forming roller (9) between successive pluralities of entrainment elements (10) distributed correspondingly in an annular pattern on its outer surface, each one of the contoured teeth (13) having a respective scraping profile (14) which is arranged substantially so as to skim the outer surface with its tip, each one of the entrainment elements (10) having a respective active portion (10a) for conveying the material to be pressed into the chamber.