Bang Sue police were alerted to the death at 11am.
The body of Boworn Chartdamrong, 20, from Surat Thani, was found on the third floor of the condominium's carpark.
Boworn lived in the room with two elder brothers. The brothers said they went downstairs to buy lunch and went to look for Boworn and found his body in the carpark.
The brothers said Boworn was stressed about his studies.