Mr Thanapol was reportedly called on the telephone at about 12.30pm yesterday to meet military authorities at a coffee shop in Soi Phahon Yothin 7.
From the coffee shop, Mr Thanapol was taken by plain-clothes military officers in a car to the 2nd Cavalry Division headquarters at Sanam Pao for questioning before being handed over to the Crime Suppression Divison police.
A lawyer for Mr Thanpol said he contacted Lt Col Burin Thongprapai, a Judge Advocate General's Department officer, who was in charge of the arrest.
The officer told the lawyer Mr Thanapol was re-arrested because he had posted a message on his Facebook page in violation of a condition for his release. The military had not filed any charges against him.
Mr Thanapol was arrested in connection with an anti-coup protest in front of the Bangkok Arts and Culture Gallery on May 23. He was one of those summoned to report to the NCPO under Order No 5.
After reporting to the NCPO, he was detained for seven days under martial law and released on the condition that he must not travel abroad or conduct political activities in a way that could spur conflicts in society.