A regulating device for regulating the air intake of an internal combustion engine, and comprising at least one throttled body having at least one air feed conduit connectable to the engine, and a first and second throttle housed in said at least one feed conduit to regulate air intake of the engine on command; the regulating device comprises a manually operated accelerator control device connected mechanically to the first throttle to rotate the first throttle about a first axis of rotation into an operating angular position related to the engine torque demanded by the user operating the accelerator control device; and electric control means for rotating the second throttle about a second axis of rotation into a target angular position determined as a function of the operating angular position of the first throttle.