The fire started in a faulty electrical transformer and quickly escalating to engulf nearby roadside shops.
Firefighters and emergency responders arrived at the scene at 7.40pm.
It took about three hours to extinguish the fire.
No injuries were reported.
Patong Police Chief Col Anothai Jindamanee said: “At this stage we believed that the fire has started from an electric transformer. However the forensic police are continuing their investigation.”
About 10 clothing and souvenirs shops were damaged or destroyed in the blaze.