The invention relates to a device for the manufacture of a prefabricated element intended to form at least part of a building. The device comprises at least two relatively movable jigs, which can be relatively fixed so that a mold can be formed in which a building element can be made to include at least two walls at an angle to each other, or a wall and a floor and/or an upper side of a section so that the element bounds at least part of the space of the building. At least one of the jigs is displaceable as a whole and coupled with driving members that displace the jig with respect to the other jig in two relatively opposite directions so that the parts can be moved away from each other or for moving the jigs in their relative manufacturing positions.