PURPOSE: To realize a countermeasure for avoiding leakage of an electromagnetic wave and grounding of a cable shield easily by a method wherein cable fixing metal fittings which clamp the cable are fixed to rails laid in a cable introducing hole and the opening parts of the rails are shielded by shielding means.

CONSTITUTION: If a cable 1 is held between a pair of cable fixing metal fittings 14 composed of tightening metal fittings 14-1 with tightening holes 14-1a and grounding fittings 14-2 with inner teeth high enough to have contact with the shielding braid 1-1 of the cable 1 and the tightening metal fittings 14-1 are coupled with each other, the inner teeth of the grounding metal fittings 14-2 break the outer covering 1-2 of the cable 1 and are brought into contact with the shielding braid 1-1 and the cable fixing metal fittings 14 are electrically continuous with the shielding braid 1-1 and the cable 1 is clamped. If the cable fixing metal fittings 14 are fixed to rails 13 laid in a cable introducing hole 2-2a and arranged, the shielding braids 1-1 are electrically continuous with the side plate 2-2 of a cabinet and a grounding connection can be provided. The cables 1 are fixed to the rails 13 and an electromagnetic wave is shut off and shielding plates 16-1 and 16-2 are attached to opening parts to which the cable fixing metal fittings 14 are not fixed to realize an electromagnetically enclosed structure.