The regulating device (1) comprises a body (2) including a hub (3) which has a first end (3a) connected to a surrounding ring (4), such as to define therebetween at least one passage (6) for the fluid, between the upstream and downstream regions, and the other or second end (3b) of which protrudes with respect to the ring (4). The ring (4) has, on a surface thereof, an annular distribution of projections (7). On the second end (3b) of the hub (3) there is mounted a flexible, ring-shaped, regulating member (8) facing and spaced from the tops of said projections (7) and capable during use of resiliently flexing towards them as a result of and depending on the difference in pressure between the upstream and downstream regions. The ring (4) is further provided with a plurality of restricted holes (10) having a fluid flow parallel to the at least one passage (6). These restricted holes (10) are formed essentially in the same radial portion (C) of the ring (4) in which the projections (7) are provided such that the holes (10) are circumferentially and radially comprised each between a pair of projections (7).