PURPOSE: To allow a circuit board for high frequency to get rid of uncontinuous parts which lie on a grounding path between the board and a housing and which may result in emission of high frequency energy.

CONSTITUTION: A circuit board 14 fitted with a grounding surface 18 on one surface is accommodated inside of a conductive housing 10. The area 22 covering the over-part of the grounding surface 18 and the wall of the housing 10 is filled with a conductive elastomer member 20 formed so as to be some higher than the area 22. A lid is put on the housing 10, and thereby a pressure is applied to the elastomer member 20 for deformation so as to fill the uncontinuous part on the grounding path between the wall of the housing 10 and the grounding surface 18.