Device for indicating the vibration level of a helicopter comprising a rotor, for producing a first vibration level VIB1 derived from a first acceleration signal γ1, this device comprising: - a first analysis means FT1 adapted for resolving said first acceleration signal γ1 delivered by one or more sensors measuring the vibrations directed along the axis of the rotor into a plurality of axial analysis signals, each γ1 i included in an identified frequency band B i, - a first memory RM1 in which are recorded a plurality of axial weighting coefficients, each KA i corresponding to one of said identified frequency bands B i, - a control circuit CC for summing the p th powers of said axial analysis signals γ1 i weighted by said axial weighting coefficients KA i, thereby producing said first vibration level VIB1; characterised in that the device receives a second acceleration signal delivered by one or more sensors measuring the vibrations directed perpendicularly to the axis of the rotor, the device comprising: - a second analysis means adapted for resolving said second acceleration signal into a plurality of radial analysis signals, each included in an identified frequency band, - a second memory in which are recorded a plurality of radial weighting coefficients, each corresponding to one of said identified frequency bands, and - a second control circuit adapted for summing the p th powers of said radial analysis signals weighted by said radial weighting coefficients in order to produce a second vibration level. - a first analysis means FT1 adapted for resolving said first acceleration signal γ1 delivered by one or more sensors measuring the vibrations directed along the axis of the rotor into a plurality of axial analysis signals, each γ1 i included in an identified frequency band B i, - a first memory RM1 in which are recorded a plurality of axial weighting coefficients, each KA i corresponding to one of said identified frequency bands B i, - a control circuit CC for summing the p th powers of said axial analysis signals γ1 i weighted by said axial weighting coefficients KA i, thereby producing said first vibration level VIB1; characterised in that the device receives a second acceleration signal delivered by one or more sensors measuring the vibrations directed perpendicularly to the axis of the rotor, the device comprising: - a second analysis means adapted for resolving said second acceleration signal into a plurality of radial analysis signals, each included in an identified frequency band, - a second memory in which are recorded a plurality of radial weighting coefficients, each corresponding to one of said identified frequency bands, and - a second control circuit adapted for summing the p th powers of said radial analysis signals weighted by said radial weighting coefficients in order to produce a second vibration level. - a second analysis means adapted for resolving said second acceleration signal into a plurality of radial analysis signals, each included in an identified frequency band, - a second memory in which are recorded a plurality of radial weighting coefficients, each corresponding to one of said identified frequency bands, and - a second control circuit adapted for summing the p th powers of said radial analysis signals weighted by said radial weighting coefficients in order to produce a second vibration level.