Abstract: A junction piece for releasably connecting rod-shaped structural elements 7, the junction piece consisting of a junction ball K and a pin element 4 to be radially screwed into the ball K. The pin elements 4 are of cylindrical shape and can be inserted with a cylindrical section into front end recesses of the structural elements 7 and can be fixed axially thereof. In this case, the cylindrical section is made to correspond to an axial guide casing for the pin element 4. The guide casing can be rotated and fixed in the front end recess of the rod-shaped structural elements 7, whereas the pin element 4 is arranged to be prevented from any rotation in the guide casing. It is, however, allowed to be axially displaced against the action of the spring 5.