The Diet on Saturday ratified a free trade agreement with the European Union, clearing a key hurdle for the tariff-cutting pact to take effect next year.
If the European Union completes its own ratification process by the end of the year as planned, the pact will come into force in February.
The House of Representatives approved the pact on Nov 29 before the House of Councillors did so on Saturday.
Japan and the European Union will create a free trade zone covering around 30 percent of global gross domestic product when the pact takes effect.
The two sides rushed to conclude negotiations that began in 2013 amid growing concern about protectionism and U.S. President Donald Trump's pushing of his "America First" agenda.
The deal will eliminate tariffs on most imports between Japan and the European Union. It also aims to encourage investment and sets rules on intellectual property protection.
Japan will abolish duties on around 94 percent of all imports from the regional bloc by 2035. The 28-nation body, meanwhile, will get rid of tariffs in stages on around 99 percent of imports from Japan, such as cars.
Japanese consumers will gain access to cheaper European products such as cheese, wine and pork under the pact.
Japan is also part of a revised Trans-Pacific Partnership free trade pact concluded without the United States that takes effect on Dec 30. Prime Minister Shinzo Abe promoted the 11-member TPP as he aims to pursue multilateral frameworks to push free trade.