At least 23 people are confirmed or presumed dead in a fire that broke out at the three-story Kyoto Animation production studio early Thursday, Japanese authorities said.
The suspect was also injured and taken to a hospital, officials said.
Police said they were still investigating the cause of the fire but that it was a suspected arson attack.
TV footage showed white and black smoke billowing out of the many windows of the ochre-hued building of Kyoto Animation.
A deadly fire which broke out at Kyoto Animation's Studio 1 building in Kyoto, Japan and took of the lives of at least 33 individuals appears to be the deliberate work of an arsonist.
The fire was nearly extinguished hours later, and firefighters were searching for anyone left behind.
▼ The Fushimi Ward studio of Kyoto Animation, whose works include The Melancholy of Haruhi Suzumiya, Lucky Star, Clanaad, K-On!
The man had been heard shouting "die" as he set fire to the building, Japanese broadcaster NHK reported.
Survivors who saw the suspect told local media that he was not one of their colleagues.
He said firefighters found the largest number of victims on the top floor of the three-story building, including some who had collapsed on the stairs leading to the roof.
Following the incident, Kyoto Animation has also chose to cancel the production of its planned Free!
Voice actor SungWon Cho tweeted: "I'm horrified to hear about Kyoto Animation, that someone could do something so disgusting to people who have brought so much joy is absolutely sickening".
Violent crime is relatively rare in Japan but occasional high-profile incidents have shocked the nation. News of the arson attack went viral on social media, with many people saying their thoughts were with the victims.
Less than two months ago, a man with a knife attacked a group of school girls at a bus stop in Kawasaki, just south of Tokyo.