The SIT filed the charge sheet at the Judicial Magistrate court at nearby Tirumangalam last evening, police said.
A powerful pipe bomb was detected on October 28 on the Jan Chetna yatra route to be taken by the BJP leader.
Advani, who was on a nation-wide anti-corruption yatra, changed his route after the five-feet long bomb, concealed by grass and a saree, was found under a culvert at Alampatti near Tirumangalam, 30 km from Madurai. The bomb was later defused.
Police had registered a case under the Explosives Act and IPC sections 120 (conspiracy) and 307 (attempt to murder).
Three persons have so far been arrested and police are on the lookout for three more.
