The man, who was arrested from his apartment in Nong Chok district in eastern Bangkok this afternoon, was reportedly found in possession of a large quantity of explosive-making materials, Nation newspaper said.
"We have detained one person," deputy national police chief General Chaktip Chaijinda told reporters on a live broadcast.
It was, however, not immediately clear if he was the same person whose sketch was circulated by authorities.
The materials included 0.5mm-diameter ball bearings that were similar to the type used with the bombs that exploded at the Shrine and at the Sathorn Bridge a day later.
His arrest was made after about 100 police and troops surrounded the apartment in which the suspect was renting two rooms. They surrounded the building on Soi Chuamsamphan 11 for about two hours before making the raid.
Twenty people were killed and more than 100 injured in the bomb blast at the Erawan Brahma shrine which took place during evening rush hour. There was a second explosion at the site the next day though no one was hurt as it occurred inside the canal water.