The leader and the party candidate, sitting MLA Devdayal Kuswaha, escaped unhurt.
Sinha was campaigning with Kuswaha and other party members in Hazaribagh Town assembly constituency for the forthcoming elections in the state when a group of people attacked them.
The incident occurred at around 1500 hours on Guru Gobind road in the centre of the town.
Sources said that a dissident party man, who was not happy with Kuswaha as the BJP candidate, was responsible for the attack.
The miscreants destroyed banners and posters carried by the campaigners. A vehicle was also destroyed in the attack.
However, no one was injured in the incident.
Kuswaha was moved to safety as soon as the attack began, but Sinha stood his ground and even made a small speech exhorting people to "vote for the party and not the candidate".
Former external affairs minister Sinha had lost the election in Hazaribagh constituency in the Lok Sabha elections in 2004.