Japanese Prime Minister Shinzo Abe will visit Iran from Wednesday to meet President Hassan Rouhani and Supreme Leader Ayatollah Ali Khamenei.
Abe will meet the two Iranian leaders in Tehran at a time of rising Middle East tensions caused by the rift between Iran and the United States.
He will be the first Japanese prime minister to visit Iran since 1978, when Takeo Fukuda visited the country shortly before the Islamic Revolution.
This year marks the 90th anniversary of the establishment of diplomatic ties between the two nations.
Abe intends to stress his resolve to further develop the countries' longtime friendship through people-to-people exchanges and technological cooperation.
He is also expected to tell the Iranian leaders that peace and stability in the Middle East are crucial for Japan, which relies heavily on the region for energy resources.
Abe plans to urge them to make a constructive response to ease tensions with the US, such as holding dialogue with Washington. He will also ask them to uphold and steadily implement the 2015 nuclear deal.
But Iran has said it will partially withdraw its compliance with the pact to protest new sanctions by the US, which unilaterally pulled out of the agreement last year.
Iran's relations with Saudi Arabia and Israel have also been chilly, making it more difficult to break the impasse.