PURPOSE: To simplify manufacturing process and also to improve yield by molding a ply with an air-inflated annular tube working as a core in a ply molding process.

CONSTITUTION: With a rubber tube 6 inflated circular in external form by air or gas or such material as is ready for fusion working as a ply molding core, a ply constituting material 1' formed in a long band is wound spirally. Next, a tread 3 and a side wall 4 which constitute an armoring are sticked on the spiral ply 1. A green tyre is molded through the above process, and in this molding method a process for bead installation and ply turnup is omitted, and further the ply can be molded very simply. Then in a vulcanizing process where a tyre is vulcanized in molds 20, 20', the bead is not required and the ply 1 is almost circular in section, therefore a construction of the molds 20, 20' is simplified.