PURPOSE: To reinforce a case main body part and improve its ridigity by arranging the inside upper end of a metal cord reinforcement layer higher than the upper end of a rolled up part.

CONSTITUTION: The terminal part of a carcass ply 11 made of a rubber-coated layer of metal cord is rolled up round a bead core 12, and a highly elastic rubber stock 13 is arranged between a case main body part 11a and a rolled up part 11b. Further, a metal cord reinforcement layer 14 is arranged outside the rolled up part 11b so as to enclose said part from the outside of a bead part to the inside via the bottom part in such a manner as its height (c) of the inside upper end from the bead base part exceeds the height (b) of the rolled up part upper end from the bead base part. Furthermore, a covering layer 15 of organic fiber cord is arranged so as to cover parts adjacent to the inside upper end of the metal cord reinforcement layer 14.