A method and a device allow for reducing the vibration generated on the structure 17 of a helicopter 2 by the air flow through the main rotor 5 and by the air flow along the fuselage 3. The device 1 includes: at least one sensor 18, 19, 20 measuring the vibration generated on the structure 17; and computer element 30 responsive to the measurements to determine a variation in angle of incidence for a stabilizer 39 of the helicopter 2 that is suitable for generating a vertical opposing force {right arrow over (TZ)} for opposing the vertical vibration, with the variation in angle of incidence as determined in this way being transmitted to a system 10 for controlling the angle of incidence of the stabilizer 39.