PURPOSE: To conceal a measuring instrument assembly body by a decorative rim by integrally providing the decorative rim with the measuring instrument assembly body and fitting the measuring instrument assembly body provided with this decorative rim in a measuring instrument installation opening part of an instrument panel.

CONSTITUTION: A decorative rim 31 is previously fixed on a measuring instrument assembly body 26 through a bracket 33, and the decorative rim fixed on this measuring instrument assembly body 26 is fixed on an instrument panel 21. As assembly work of the measuring instrument assembly body 26 and the decorative rim 31 can be previously carried out in an assembly line, for example, by an automatic assembly means at a distance from a car body, and accordingly, its assembly workability can be extensively improved. Additionally, as assembly dimensional precision of the measuring instrument assembly body 26 and the decorative rim 31 is easily controlled, it is possible to assemble the measuring instrument assembly body 26 and the decorative rim 31 with smallest possible clearance between them, and a concealing effect by the decorative rim is improved.