Twenty-eight-year-old Kazuto Ioka, who won world titles in three separate weight classes, announced Sunday that he will hang up his gloves and retire from the ring.

"I'm satisfied with myself because I could win in three classes, which is also the reason why I started boxing," Ioka told a press conference.

In a message to his fans, he said, "I think I'm here now because of your support, and I want to express my greatest appreciation."

In 2012, in the third defense of his WBC minimumweight crown, Ioka won the WBA minimumweight title from champion Akira Yaegashi, becoming the first Japanese fighter to unify a title sanctioned by those two bodies.

In 2014, he failed to win the IBF flyweight crown in the only loss of his career, but took the WBA flyweight belt the following year and defended it four times.

Ioka was scheduled to defend that title for a sixth time on Sunday, but relinquished his belt in November, after his father announced he wasn't ready to fight due to insufficient training following his marriage to singer Nana Tanimura.

Back in November, the elder Ioka told a news conference his son had been scheduled to defend his title for the sixth time on Dec. 31, but he would not be ready because he has not been able to keep up his training after getting married earlier this year.

At the time, the 28-year-old boxer’s future plans were undecided, his father said.

“If he is up for it, I am ready to train him any time,” Kazunori Ioka said. “If he doesn’t have the motivation, he has no choice but to retire. It’s one or the other.”

When asked if his marriage had affected his decision to retire, Ioka said, "I haven't felt any influence fighting since we've been together. My wife's presence itself was my support."

The younger Ioka won 13 title match victories in his career, going 22-1 with 13 KOs.