A green tire forming method comprising a tubular carcass with cores forming process to form a tubular carcass (6R2) with bead cores on a first drum, which comprising a tubular carcass forming step (K1a) comprising winding (K1a1) a sheet-like carcass ply member (6R1) on an outer periphery of the fi rst drum in a single layer, and a bead core joining step (K1b) comprising putting a pair of bead cores on radially outwardly and axially both end sides of the tubular carcass (6R2) on the first drum, and expanding a diameter of the first drum with the tubular carcass (6R2) so that the tubular carcass (6R2) is pressed against an inner periphery of bead cores and firmly jointed thereto; a rubber laminate forming process to form a cylindrical rubber laminate having a smaller outside diameter than an inside diameter of said tubul ar carcass (6R2) by wi ndi ng rubber members (Ga) for a base tire including an inner liner rubber member (G10a) on an outer periphery of a second drum which is expandable in a diameter; a first transport process to transport said tubular carcass with bead cores (6R3) from said first drum to the second drum by use of a transfer, and to maintain concentrically the tubular carcass with bead cores (6R3) radially-outside the rubber laminate on the second drum; a tubul ar base ti re forming process by expanding the outside diameter of the second drum with the rubber laminate so that the rubber laminate is pressed against the inner periphery of said tubular carcass with bead cores (6R3) so as to form a tubular base tire formed by jointing integrally said rubber laminate with the tubular carcass with bead cores (6R3); characterized by a second transport process to transport said tubular base tire from said second drum to a shaping drum by use of a transfer, wherein the tubular carcass forming step (K1a) further comprises butt-jointing (K1a2) each circumferential end face of the carcass ply member (6R1) each other, and wherein a diameter-expanding ratio Db/Da of an outside diameter Db of the expanded second drum to an outside diameter Da before diameter-expanding thereof is in a range of 1.025 plus/minus 0.01. a tubular carcass forming step (K1a) comprising winding (K1a1) a sheet-like carcass ply member (6R1) on an outer periphery of the fi rst drum in a single layer, and winding (K1a1) a sheet-like carcass ply member (6R1) on an outer periphery of the fi rst drum in a single layer, and a bead core joining step (K1b) comprising putting a pair of bead cores on radially outwardly and axially both end sides of the tubular carcass (6R2) on the first drum, and expanding a diameter of the first drum with the tubular carcass (6R2) so that the tubular carcass (6R2) is pressed against an inner periphery of bead cores and firmly jointed thereto; a rubber laminate forming process to form a cylindrical rubber laminate having a smaller outside diameter than an inside diameter of said tubul ar carcass (6R2) by wi ndi ng rubber members (Ga) for a base tire including an inner liner rubber member (G10a) on an outer periphery of a second drum which is expandable in a diameter; a first transport process to transport said tubular carcass with bead cores (6R3) from said first drum to the second drum by use of a transfer, and to maintain concentrically the tubular carcass with bead cores (6R3) radially-outside the rubber laminate on the second drum; a tubul ar base ti re forming process by expanding the outside diameter of the second drum with the rubber laminate so that the rubber laminate is pressed against the inner periphery of said tubular carcass with bead cores (6R3) so as to form a tubular base tire formed by jointing integrally said rubber laminate with the tubular carcass with bead cores (6R3); characterized by a second transport process to transport said tubular base tire from said second drum to a shaping drum by use of a transfer, wherein the tubular carcass forming step (K1a) further comprises butt-jointing (K1a2) each circumferential end face of the carcass ply member (6R1) each other, and wherein a diameter-expanding ratio Db/Da of an outside diameter Db of the expanded second drum to an outside diameter Da before diameter-expanding thereof is in a range of 1.025 plus/minus 0.01. putting a pair of bead cores on radially outwardly and axially both end sides of the tubular carcass (6R2) on the first drum, and expanding a diameter of the first drum with the tubular carcass (6R2) so that the tubular carcass (6R2) is pressed against an inner periphery of bead cores and firmly jointed thereto;