The inferno broke out in Beijing’s southern Daxing district, Xinhua news agency said, citing local authorities.
The report did not specify the cause but said an unspecified number of suspects were in police custody.
Xinhua said the fire was brought under control some three hours after it erupted and that the injured had been rushed to hospital.
Deadly fires are common in China, where fire safety regulations are widely flouted and enforcement is often lax.
Eleven people died in September when a fire broke out in two houses in the eastern city of Taizhou.
© Agence France-Presse