Abstract: Improved constructional building set comprising as its basic elements a plurality of linking units, each linking unit comprising at least one connecting rod with a generally ball shaped head portion at each end thereof. A plurality of coupling members engage the head portions to couple the linking units. These coupling members have a clamping construction which tightens such that a pair of clamping members are urged toward each other about the rod head portions. Thus provided is a building set which is easy and inexpensive to manufacture and affords numerous possibilities of assembling stable structures. Such structure is useful not only as construction toys, but also for the construction of articles for everyday use.