The 24-year-old actor was convinced that another young actor could take over the part from him after 2004's 'Harry Potter and the Prisoner of Azkaban', reported Contactmusic.
"By the third film, I thought, if there's a time to get out, it's now; there's still enough time for another actor to come in and establish himself," Radcliffe said.
"For a while, I thought, if I do all of them, will I be able to move on to other stuff or should I start doing other stuff now?," he added.
"But in the end I decided I was having way too much fun. And actually there aren't many great parts out there for teenage boys, certainly not as good as Harry Potter.