PURPOSE: To make fixation to ALC material rigid with elasticity of a fixing leg by constructing an insulated staple while driving the fixing leg provided with a fixing hole with a smaller diameter of the leg part into the two leg parts having parallel nail shafts.

CONSTITUTION: An insulated staple U is formed by driving fixing legs 1 into parallel leg parts 6 of having U-shaped metal nail shafts 5. The fixing leg has a bar-like shape and a slender fixing hole 2 is formed on the inner center part thereof. The fixing hole is taperedly formed such that the upper inner diameter thereof is a little narrower than the outer diameter of the leg part 6, then becomes the same at the bottom part. The fixing leg 1 is made of rein forced resin strong enough to stand driving. When the fixing leg is driven into the leg part 6, a slight taperness is formed on the outer form. A cable 9 is fixed to a cable fixing member 10 rigidly by the elasticity of the resin material, even if the cable fixing member 10 is made of ALC material and the conven tional insulated staple is not available.