Back in August, a woman in Tokyo had an emergency C-section at just 24 weeks and gave birth to a baby boy who was 268 grams . . . which is only 9.45 ounces.

Well . . . that tiny baby has made a giant comeback.

Over the course of the past several months, he’s managed to pack on 12 times his birth weight. He’s now up to seven pounds, two ounces.

On Tuesday, two months after his official due date, he was sent home from the hospital, totally healthy . . . and that makes him the smallest baby boy EVER to survive.

The smallest girl who’s ever survived was 8.89 ounces. She was born in Germany in 2015.

Overall, only 23 babies worldwide who weighed under 300 grams, or 10.58 ounces, have ever survived . . . and only four of them are male.