Deputy Inspector General of Police Sheetal Oraon said the policemen were on patrol duty when a group of Maoists fired indiscriminately on their vehicle killing three of them on the spot.
Two others succumbed to their injuries at separate hospitals.
Three Insas rifles of the police were also taken away by the red rebels from the spot, about 150 km from Ranchi, the DIG said.
Director General of Police Rajeev Kumar has reached the spot.
The Maoists are reportedly observing a protest-week since April 1 to protest against the March 28 massacre of 10 Maoists in Chatra district by ultras of the Trititya Prastuti Committee, a break-away group of the CPI (Maoist).
The red rebels have also called a 48-hour bandh in Jharkhand and Bihar from April 6.