The vehicle in which two Japanese envoys in Baghdad and an Iraqi driver were shot to death in northern Iraq arrived at Narita airport near Tokyo on Thursday night, more than three months after the attack.
Police are expected to inspect the four-wheel-drive vehicle, which has about 30 bullet holes in its left side.
Senior Vice Foreign Minister Masatoshi Abe told a news conference earlier in the day that it took so long to ship the sports utility vehicle because Japan was consulting with U.S. coalition authorities in Iraq.
The vehicle was transported in a container and is not to be shown to the media because it is evidence in a criminal case, according to a senior Foreign Ministry official.
The ministry also took into consideration the feelings of the victims' families, the official said.
Katsuhiko Oku and Masamori Inoue were killed just before the government announced the basic plan to dispatch Self-Defense Forces personnel to Iraq.