Police and firefighters were called to the scene, just two doors down from Chalong Police Station on Chao Fa East Rd, at 10:30am.
Officers closed traffic at Chalong Circle while firefighters took 15 minutes to douse the blaze, which broke out on the second floor.
Neighbours reported the fire after seeing black smoke coming out from the second floor unit.
No other units were affected by the fire, police confirmed, and no injuries were reported.
Police have yet to release an estimate of the damage caused by the fire.
An investigation into the cause of the fire is underway, although an electrical short circuit is already believed to have started the fire.