A valve flap device for opening and closing a bypass valve of a turbocharger is provided. The valve flap device includes a valve spindle, a flap support arranged on the valve spindle and having a through aperture, a cover disk in the form of a circular ring, and a valve flap arranged on a support lower side of the flap support on the support lower side. The valve flap includes a flap plate and a flap support pin arranged on the flap plate rear side and is passed through the through aperture of the flap support and is firmly connected to the cover disk. A spring element is installed in the spring gap under a preload. A centering device, provided on the support upper side, is arranged concentrically with the central axis of the through aperture and keeps the spring element in a centered position relative to the central axis.