His wife is also an ex-governor of Rio state, winning election to one term to replace her husband.
Anthony Garotinho, who served from 1998 to 2002 before mounting an unsuccessful run for the presidency, "was taken into preventative detention as part of a police operation probing electoral fraud," a spokesman for the federal police in the town of Campos told AFP.
Police were investigating an alleged vote-buying scheme in Campos, in the north of Rio state, during October nationwide municipal elections.
Garotinho was accused of "extremely serious criminal actions which defrauded the municipal elections with the aim of aiding... preferred candidates," the judge's order for the detention said.
Garotinho, a member of the Brazilian right's increasingly powerful evangelical wing, is currently serving as number two to the outgoing mayor of Campos -- his wife Rosinho Garotinho.
His wife is also an ex-governor of Rio state, winning election to one term to replace her husband. However she lost in the October elections and will stepdown as mayor.
Brazil is in the midst of major political upheaval sparked by a probe into high-ranking bribery and embezzlement centered on state oil giant Petrobras. The scandal, known as Operation Car Wash, has seen former presidents, ministers and other top officials charged with bribery and other crimes.