COLUMBIA, S.C. — A former South Carolina treasurer, Thomas Ravenel, pleaded guilty yesterday to a federal charge of possessing with intent to distribute cocaine. Ravenel, 45, acknowledged during a hearing that he bought cocaine from several different people, and said he used the drug sometimes as often as once a week.

Ravenel, who resigned a month after his June indictment, would not speak to reporters after his court appearance.

Prosecutors have said Ravenel bought the cocaine to share with friends, not to sell.

Ravenel, a multimillionaire developer, faces up to 20 years in prison and a $1 million fine, though his plea agreement calls for a reduced sentence if he helps prosecutors with their investigation.

Two other people also have been charged in Ravenel’s case.

Ravenel has spent a month each in rehabilitation facilities in Arizona and New Mexico. His attorneys have refused to say what kind of treatment he received, but his father, a former House lawmaker, Arthur Ravenel, has said his son has a drug problem. Yesterday, Ravenel told the judge he did not receive drug treatment. “It had more to deal with why I was acting so recklessly,” he said. Ravenel is expected to be sentenced in a few months.