To provide an easily mountable reinforcement metal wire supporting spacer supporting a reinforcement metal wire on a floor while keeping a necessary dimension.

In this supporting space for concrete reinforcement metallic wire, a supporting base 2 integrally molded of a plastic resin and the like is formed into a wedge shape in a lateral side view, and an engaging part 3, in which an opening part dimension of an upper face entrance is set to be slightly smaller than an outside diameter dimension of a welded wire mesh, for engaging the welded wire mesh having a bottle shape in the lateral side view and is arranged on one end side of the supporting base 2 by cutting a lateral groove horizontally crossing the longitudinal direction of the supporting base. In the lower part edge on the opposite side of the engaging part 3, an insertion part 4 projected forward is arranged for fixing the welded wire mesh and preventing it from coming off. In addition, a step-shaped rugged part serving as a nonslip part 6 is arranged on the slant face for preventing the spacer from being pressed and returned by a load of the welded wire mesh and the like.