Fabrication of a full-scale sector model of the ITER vacuum vessel, which was initiated in 1995 as one of the Large Seven ITER R&D Projects, was completed in September 1997. The full-scale sector model corresponds to an 18° toroidal sector, is composed of two 9° sectors, Sector A and B, which are spliced at the port center according to the current ITER design. In order to satisfy tight manufacturing tolerances of ± 5 mm and to assure the structural integrity of a double-walled structure, a combination of Gas Tungsten Arc (TIG)/Electron Beam (EB) welding and TIG/Gas Metal Arc (MIG) welding were adopted for Sector-A and B, respectively. Although the different fabrication procedures and welding techniques were employed for the fabrication, both sectors have successfully satisfied the dimensional accuracy of ± 3 mm for the total height, total width and total wall thickness. After the completion of fabrication, both sectors were shipped to the test site in Japan Atomic Energy Research Institute (JAERI) and assembly test was begun in October 1997. The first demonstration test of automatic narrow gap TIG welding of the field joints between sectors was successfully completed at the end of May 1998. This paper outlines the design and fabrication procedures and describes the results of the fabrication and assembly test of Sector A and B.