Herein disclosed is a tire valve core mounting apparatus for mounting one or more valve cores into one or more valve stems. The tire valve core mounting apparatus comprises an annular member adapted to be intermittently rotated through a constant angle and having therein a plurality of valve stem holding bores being in circumferentially equidistant relation with respect to one another, each valve stem holding bore extending radially of the annular member, and a plurality of locking mechanisms mounted on the annular member for locking the valve stem in the valve stem holding bores, a valve core supplying and screwing arrangement fixed with respect to the annular member for supplying a valve core to a valve stem held in one of the valve stem holding bores per an angle of rotation of the annular member and for screwing the valve core into the valve stem, and disengaging means fixed with respect to the annular member and spaced in the rotation direction of the annular member from the valve core supplying and screwing arrangement for disengaging the valve stem from the valve stem holding bore.