The fire broke out around 4.30 p.m. The injured were shifted to the city's Meo Hospital.
Some of the injured suffered severe burns, Xinhua reported.
The toll may increase, hospital sources said.
The blaze was brought under control.
The owner of the factory and his son were also killed in the fire. Police said the factory was not registered.
Rescue work was underway as there were still some workers trapped inside.
An initial probe showed the fire broke out due to short circuit.