Won Sei-Hoon, the former director of the National Intelligence Service (NIS), was held after a court issued an arrest warrant requested by prosecutors, Yonhap news agency reported.
The 62-year-old is suspected of having received some 150 million won (USD 132,000) in cash and expensive gifts from Hwang Bo-Yeon, the head of now-bankrupt Hwangbo Construction, it said.
In return, prosecutors believe Won peddled his influence to help the company win construction projects, Yonhap said.
Won, who served as the country's spy chief under former President Lee Myung-Bak, is on trial on separate charges of meddling in last year's presidential election.
Several days before the presidential election on December 19, allegations that NIS agents were trying to manipulate voters online emerged, sparking a police probe.
Liberal opposition candidate Moon was defeated in the election by conservative Park Geun-Hye.