The Grand New is a twin-engine, eight-seat aircraft with a maximum speed of 177 miles per hour and a ferry range of nearly 600 miles.
It features digital avionics for single/dual pilot Instrument Flight Rules operation and a four-axis dual duplex digital autopilot coupled with a Flight Director.
Japan's National Police Agency will use the aircraft in the country's Saga and Tottori prefectures.
AgustaWestland said the order is the first for Grand New aircraft to the agency and is part of the police initiative to modernize its helicopter fleet.
"This latest order is further evidence of the growing success we have experienced in the Japanese helicopter market in recent years, meeting commercial, government and military requirements by offering the best solutions and establishing strong relationships with our local partners," said Andrew Symonds, president, AgustaWestland Japan.
"We are committed to building on this success by offering the best solutions for future rotorcraft requirements in Japan."