The young girl was injured when a metal brace suddenly detached itself from the Ferris wheel and struck her as she was walking nearby with her parents on Monday evening.
The girl lost a substantial amount of blood and was taken to a hospital in the city of Bari, where she remains in a stable condition, reports Repubblica.
The amusement park had been set up as part of the mid-August festivities in honour of St Mary of Consignano, a religious celebration in Giovinazzo, just north of the city of Bari.
The girl's mother was also struck by the piece of metal that fell from the ferris wheel, according to Rai News.
Local police ordered the ferris wheel to be closed and are investigating the incident. No one else was reported injured.
Such accidents are rare but not unheard of. A six-year-old girl was injured in a ride at Gardaland in 2016. Two teenagers also suffered heart attacks in 1999 and 2001 respectively at the Italian amusement park, according to news portal Lettera 43.