Prime Minister Prayut Chan-o-cha will lead more than 50 delegates to Japan next week to sign two major agreements on a railway project development and business cooperation.
Aside from bilateral and regional discussions, the visit will boost ties between the countries, a Government House statement said.
The visit, from Sunday to Tuesday, is aimed at improving relations economically and bolstering Japan's confidence in Thailand.
Japan is an economic superpower and a close ally of Western countries and the visit will be an indication of the warm relations which Thailand enjoys with the Japanese, the statement added.
"The welcome from Japan is an important signal that they accept and honour the Thai leader and acknowledge the country has made progress in moving towards democracy," it said.
The visit would also reaffirm the country's stance that Japan is a key partner playing a significant role in Thailand's economic development.
The trip will also try to balance relations between China and Japan.
During his visit, Gen Prayut will meet his Japanese counterpart Shinzo Abe on various aspects of collaboration, covering economic, security and regional issues.
The two premiers are expected to address their countries' long-standing relationship in all aspects, especially trade and investment.
The prime minister will also meet some Japanese lawmakers from the ruling Liberal Democratic Party, the Japan Business Federation (Keidanren) and other private sector parties.
Four key figures from four major Japanese companies — Mitsubishi, Mitsui, Honda and Marubeni — will meet Gen Prayut separately, the source said.
Gen Prayut and Mr Abe will witness the signing ceremony of a memorandum of intent (MOI) on cooperation in rail system development that Transport Minister ACM Prajin Juntong and his Japanese counterpart are scheduled to sign together.
Under the MOI, Japan will take part in three sections of the railway project which Gen Prayut said was key to strengthening relations.
The proposed East-West Economic Corridor railway routes are from Bangkok to Kanchanaburi (Ban Phu Nam Ron), Bangkok to Aranyaprathet in Sa Kaeo, and Bangkok to Laem Chabang in Chon Buri.
A memorandum of cooperation on business cooperation will be signed by the Japan External Trade Organisation and the Joint Committee of Thai Chamber of Commerce, Federation of Thai Industries and the Thai Bankers' Association.
Cooperation on the Dawei project will be among the highlights of Gen Prayut's visit to Japan.
The Thai cabinet earlier approved a draft memorandum of understanding on an economic partnership arrangement with Japan featuring cooperation over the long-awaited multi-billion-dollar Dawei megaproject in Myanmar, along with other areas of cooperation in a new rail network and trade and investment promotion.
According to the government, Japan will take part in the Dawei project and possibly offer soft loans to construct a 138km road between Dawei and the Thai border which will also support the government's special economic zones (SEZs).
The agreement was struck in a recent meeting between Thailand, Japan and Myanmar officials.
Japan has also agreed to hold an equal partnership in the Dawei SEZ Development Co (DSEZ), a special-purpose vehicle (SPV), to run the project.
DSEZ replaced Italian-Thai Development Plc (ITD), which had been awarded the original concession by the Myanmar government in November 2010. ITD decided to pull out of the scheme.
In June 2013, Thailand and Myanmar agreed to set up DSEZ with equal shareholdings and an initial investment of 12 million baht, far below the 100 million baht that had been proposed earlier.
The company is registered in Thailand.
The countries also agreed to set up SPVs to manage the port, road and rail links, power plants, waterworks, industrial estates, telecommunications and a township.
The SPVs will be registered in Myanmar.