The Japan Rugby Football Union (JRFU) added they had sent a letter of intent to the International Rugby Board confirming the country's bid for both the 2015 and 2019 tournaments.
By submitting a letter of intent for both World Cups, Japan can keep the option open to bid for either, or both, in their final tender to the IRB next year.
"We are bidding to host the Rugby World Cup not just for Japan but for Asia," said JRFU chairman Nobby Mashimo.
"Bringing the [tournament] to Japan and Asia will unlock the potential of rugby as a truly global sport."
The country lost out to New Zealand in the bidding for the 2011 World Cup.