The present invention aims at improving balance and uniformity of a tire, with simplifying facilities, reducing space for the facilities and suppressing shape flows and generation of air bubbles. An extruder is provided for supplying rubber ribbon immediately after extrusion to a second molding drum, so that the rubber ribbon is spirally wound around the second molding drum plural times to structure a portion of tread (a cap layer), whereby the rubber ribbon which is relatively hot and soft is wound around the second molding drum. As a result, the rubber ribbon easily deforms compliant to the second molding drum. Further, no joint portion of starting and terminal ends as is observed in the prior art exists, whereby thickness of the tread is even in the circumferential direction.