No one else was injured Saturday afternoon at the venue in Trotwood, Ohio.
The accidental shooting happened outside Hara Arena in suburban Dayton where there was a gun and knife show.
Trotwood police told The Dayton Daily News the man had just bought a holster and was putting a handgun in it when the gun fired.
Police said a bullet struck a finger on his left hand. They said they don’t expect to file any charges.