The blaze at the store near Villa 5 in Chao Fa West broke out about 2am. Six trucks brought it under control in 90 minutes.
''Five staff and 10 customers were in the store when the fire began,'' said an officer from Vichit Police Station. ''We believe the cause was probably an electrical fault.''
Damage is estimated at 10 million baht.
SuperCheap's rambling main store was destroyed in October 2013 in one of the most spectacular fires seen on Phuket. There was no loss of life or injuries.
The original Phuket brand had diversified tinto smaller outlets across the island to meet competition from franchised convenience store brands.