By Agence France-Presse
Police and troops organised a search and rescue operation after the helicopter plunged into a forest Friday in Gunma prefecture, northwest of Tokyo.
"All the nine people were confirmed dead by noon today," a local official told AFP.
The victims were disaster management officials and firefighters as well as the pilot and an aviation mechanic, the official said.
Aerial footage broadcast on Japanese television showed the wreckage of the crashed helicopter surrounded by trees, as the government dispatched aircraft accident investigators to the site.
The Bell 412 helicopter left its base Friday morning on a two-hour flight to observe climbing routes from the air but did not return and lost contact with air traffic control.
In February, two pilots were killed in a military helicopter crash in southern Japan. The helicopter went down seven minutes after takeoff, slamming into and setting fire to a house, which was completely destroyed in the accident.
Last year, nine people aboard a helicopter were killed after it crashed during a mountain rescue drill.