A horizontal road sign device (10) comprises a base body (12) of a substantially planar type, able to be associated with a roadway (14). The base body (12) is made of a rubber based material and has an upper surface (20), on which motor vehicles are able to pass. The signaling device (10) comprises one or more signaling elements (16) able to determine a desired visual sign, which are at least partly incorporated into the upper surface (20) of the base body (12), having at least a visible signaling surface (18, 19, 21) facing toward the outside of the base body (12).