The man was “referred to prosecutors for allegedly violating postal law,” a Kanagawa prefectural police spokesman told AFP on Friday.
Local media reported the 61-year-old had around 24,000 undelivered items from between 2003 and 2019 at his home in Kanagawa, near Tokyo.
He reportedly told the police “it was too much bother to deliver them.”
“I didn’t want my colleagues to think I was less capable than younger people,” he added.
If convicted, the man faces prison time of less than three years or fines of up to 500,000 yen ($4,500), the police spokesman said.
Japan Post fired the man after the issue came to light late last year, and it apologized for the failure to deliver, pledging to ensure the newly discovered items of mail finally make it to their intended destinations.