Abstract: A large number of bead holding segments (30) are disposed along outer circumferences of a pair of drums (2, 2a). The bead holding segments can approach to and separate from each other in such manner that they can be expanded and contracted in the radial directions by means of an expanding/contracting mechanism (13, 17). A green tire is built and shaped while bead portions (3a) at the opposite ends of a green case (3) are being held by the segments (30). A bead holding unit (20) provided with the bead holding segments (30) and a drum main body section (10) provided with the expanding/contracting mechanism (13, 17) are formed separately from each other so that they can be freely mounted and dismounted, and the unit (20) is fixed to and released from the main body section (10) by means of a releasing mechanism (25, 6) provided on the side of the drum main body. Upon switching of a tire diameter size, only the unit (20) is replaced.