A vent plug is mounted in a vent hole open in a molding face of a tire cure mold. The vent plug has a cylindrical housing having a vent path in itself, a stem that is inserted into the housing and serves as a valve element for opening and closing the vent path, and a coil-shaped spring that biases the stem toward a cavity so as to open the vent path. The stem includes a columnar trunk portion and a head portion that comes in contact with a valve seat at an opening portion of the housing to thereby close the vent path. The stem turns as the stem moves along an axial direction.