PURPOSE: To fit a radio wave absorbing mat with a simple work, to attain sufficient mount strength and to prevent deformation in the radio wave absorbing mat, a change in the radio wave absorbing characteristic and unnecessary radiation.

CONSTITUTION: A double-side adhesive tape 2 is fitted to a prescribed position of a swelled plane NP of a mounted face member N made of a corrugated iron plate, a high viscocity resin group adhesives 3 is applied on an area between the double side adhesive tapes 2, the end at the back side of the radio wave absorbing mat M is adhered to the double side adhesive tape 2 and the middle part is adhered by the high viscosity resin group adhesives 3.