The Most Rev Justin Welby told the Independent Inquiry into Child Sexual Abuse that it was “horrifying” to read the evidence from survivors.
“I have learned to be ashamed again,” he said.
The three-week hearing is looking into the Diocese of Chichester, where dozens of clergy have been accused of abuse.
Mr Welby said: “To read the transcripts, to read the evidence, to meet the survivors, is horrifying to a huge degree, because you see this extraordinary and atrocious willingness to turn a blind eye to things going very seriously wrong and entirely damaging human beings for their whole lifetimes.”