Prosecutors had asked a court to issue an arrest warrant for Kim Han-sik, president of Chonghaejin Marine Co, over allegations of cargo overloading, according to a judge at the court in the port city of Mokpo.
Mr Kim was detained yesterday, wearing a cap and a mask. He told reporters at a detention facility in Mokpo: "I feel very sorry for the victims .... their family members. I committed a grave sin." He declined to comment on questions over alleged cargo overloading.
Authorities believe improper stowage and overloading of cargo are one possible reason the ferry sank on April 16.
Four employees at Chonghaejin Marine Co, who handled cargo on the Sewol, have already been arrested, and Mr Kim faces allegations that he was aware that the ferry exceeded its cargo limit but did not do anything before it started its trip.