Schoolgirl Ana Paun was attacked by a American bully XL and Staffordshire bull terrier crossbreed in Bordesley Green on Saturday, suffering serious injuries to her arm and shoulder.
Two other people were also injured after the dog broke free from its collar twice.
Speaking about the incident earlier this week, the youngster said: “I got terrified and he jumped on the arm and he bit me.
“I was screaming and I couldn’t do anything, the dog kept on staying on my arm.”
Ana’s mother, Monica Paun, said her daughter was taken to hospital in an ambulance after the incident and needed around eight stitches.
A West Midlands Police spokeswoman said: “A 60-year-old man has been arrested on suspicion of possessing a dog dangerously out of control.
“He has been bailed with conditions while inquiries continue."
The force confirmed the dog remains in secure kennels.
Footage of the incident sparked concern and prompted Home Secretary Suella Braverman to seek “urgent advice” on whether the breed should be banned.
Some campaigners have called for American bully XL dogs to be added to the banned list, pointing to attacks involving the breed.
However, the Dog Control Coalition, a group including the RSPCA, has argued that banning specific breeds is not the solution and that measures promoting responsible pet ownership are needed instead.