Six months after declaring that he was ruined and penniless, former Maryland Governor Marvin Mandel has leased a $300-a-month office for a fledging consultant practice.

Mandel's license to practise law was suspended last month because of his corruption charges.

Mandel, who escaped heavy fine for his conviction because U.S. District Judge Robert Taylor was concerned about his economic conditions, vacationed in Florida over the holidays. He pays $650 a month for this Anne Arundel County home.

During his trial, Mandel was shown to be a man who accepted gifts like Florida vacations from his friends. In fact, he was convicted for accepting some $300,000 worth of favors from his closest companions in return for political favors.

The former governor is appealing his conviction, though, and in the meantime - possibly one year - he has decided to set up a consulting practice, friends say.

Friends say that Mandel hopes to break into the management consultant business using his government skills as his calling card. The office, in Arnold, Md., on Ritchie Highway, in a modern three-story professional building, will be his base but he hopes to ply his trade with old Baltimore connections, friends added.

Collin F. McGowan said he leased the top-story suite to Mandel earlier this winter and that the former governor will move in shortly. "The building is 4 years old but we added the top story just six months ago. When the work is completed he (Mandel) will be in."