The clash broke out between supporters of Congress candidate Videsh Singh and Independent candidate Kushwaha Sashibhushan Mehta near an election meeting.
All the injured were admitted to a nearby hospital, the police said.
Inspector General of Police (Palamau range) A Natarajan said additional forces were deployed at the place and the district SP was asked to give a detailed report.
Meanwhile, a campaign vehicle of the JMM were set afire in Gumla Assembly constituency by Maoists today.
The Maoists took responsibility by leaving a banner at the spot, he added.
The red rebels had torched a campaign vehicle of the BJP on November 18 at Pathgatha village under the same police station.