A Japanese man sentenced to death for an arson attack on an anime studio that killed 36 people in 2019 said he accepted the court's verdict, a local media report said.

Shinji Aoba, 45, was convicted on Thursday over the blaze at the studios of Kyoto Animation -- Japan's deadliest crime in decades.

On Friday, his defence team, who had entered a plea of not guilty claiming he had a mental disorder, appealed the ruling.

But in a rare interview with the Asahi Shimbun newspaper published late Saturday, Aoba said: "I seriously accept the verdict."

He told the daily that he chose to appeal "because I would not be able to speak out if I did not continue (with the court case)".

The interview took place a day after he was sentenced.

"As the person who caused this incident, I tried to speak as much as possible during the (court) proceedings.

"But there are a few more things that I want to leave behind as lessons for others," he was quoted as saying. 

Japan is one of the few developed countries with capital punishment and public support for it is high.

As of December, 107 people were on death row.

Many of those killed in the July 2019 fire were young, including a 21-year-old woman.

Aoba broke into the building, spread gasoline around the ground floor, lit it and shouted "drop dead", according to survivors.

The victims "were engulfed in fire and smoke in the blink of an eye... They died an anguishing death as the studio instantly turned into a hell", presiding judge Keisuke Masuda said in his ruling.

"Immolating people is truly cruel and inhumane," the judge added.

Aoba himself sustained burns on 90 percent of his body and only regained consciousness weeks after the fire, and the ability to speak later still.

Aoba believed that the studio -- known by its fans as KyoAni -- stole his ideas, prosecutors said, a claim the company has denied.