Abstract: A cable elongation or relaxation measurement apparatus comprises an elongated beam having spaced apart clamp assemblies for forcibly clamping a section of cable under tension. One of the clamp assemblies is slidably mounted on a pair of parallel bearing rods secured to the beam and is centered between opposite ends of the rods by coil springs. The movable cable clamp assembly supports a dial indicator which is engageable with an adjustable fixed abutment member supported on the beam so that movement of the movable clamp assembly can be measured for a known change in load on the cable. The support beam includes a pair of spaced apart support roller assemblies each including an upstanding bracket supporting a first roller and a movable support plate supporting a second roller. The second roller may be moved relative to the first roller between a cable engaging and clamping position and a position which permits mounting and demounting the apparatus with respect to the cable.