Security officers of the 26-storey luxury condo alerted police at 6:45am that a foreign woman was killed in the fall.
She was identified as Emi Kato, 35. Her body was sent for a post-mortem at the Chulalongkorn Hospital.
Police checked her room and did not detect any sign of foul play.
Officers said they learned from her friends and neighbours that the woman has been troubled by chronic ailments.