Abstract: A highly dense spacer in which multiple ducts to longitudinally accommodate a variety of cables are arranged, and which includes a spacer body having a groove for weight reducing; a binder for binding two spacer bodies through an end side of the groove on each spacer body; and a mover for moving in one way which is facilitated on the surface of a space body. Therefore, the highly dense spacer easily and stably installs a variety of cables without using distinct inner ducts.