An automatic transport system for green tires between a forming process and a vulcanizing process in a tire manufacturing installing in which different kinds of tires are manufactured through a forming process of making use of a plurality of forming machines and a subsequent vulcanizing process making use of a plurality of vulcanizing machines. The automatic transport system comprises pallets each adapted to be charged with four or more formed green tires and to be used for transporting them as one unit. A temporary storage is interposed between a forming machine group and a vulcanizing machine group for temporarily storing the pallets at predetermined locations. Forming side unmanned transport trucks circulate between the forming machine group and the temporary storage with the pallet loaded thereon. Vulcanizing side unmanned transport trucks circulate between the temporary storage and the vulcanizing machine group with the pallet loaded thereon. Associated with the respective forming machines, a device places green tires into the pallet and loads the pallet onto the forming side unmanned transport truck. Associated with the respective vulcanizing machines, a device unloads the pallet from the vulcanizing side unmanned transport truck and discharges green tires from the pallet. Associated with the temporary storage, a device carries a green tires from the forming side unmanned transport truck, and associated with the temporary storage another device carries green tires onto the vulcanizing side unmanned transport truck. A control system controls travel of the forming side unmanned transport truck and the vulcanizing side unmanned transport truck in response to truck demands issued form the respective forming machines and vulcanizig machines, independently of each other.