Secondary explosions continued for more than an hour afterwards, BNO News reported. Rescuers couldn't access the scene until the rockets finished exploding.
National head of emergency services, Luis Felipe Puente, said the number of wounded could rise.
The Red Cross sent 10 ambulances with 50 officers to the market to put out the blaze. Fire crews struggled for three hours before bringing the blaze under control.
Tultepec is north of Mexico City and is famous for its fireworks industry. The town hosts an annual National Pyrotechnic Festival.
A fire engulfed the same market in 2005, touching off a chain of explosions that levelled hundreds of stalls just ahead of Mexico's Independence Day. A similar fire also destroyed hundreds of stands in September 2006.
The market has more than 300 stalls.
Many in Mexico traditionally celebrate holidays, including Christmas and New Year, by setting off noisy firecrackers and rockets.
