This study intended to develop an automatic production system for grafted seedlings on the basis of “Plug-in Method”, which satisfies the conditions in the view of plant histological and physiological standpoints. By auto mechanization or robotization in the production of grafted seedlings which has ever been processed by handmade, we will try to find the principle of maximumizing the production potential of seedlings. We fabricated the full automatic type of the grafting robot system to perform “Plug-in Method”. In this paper we report the parts of robotization feeding materials for grafting seedlings. Especially we measured the physical properties which is useful for design of gripper in the handling system. In the transferring of a seedling, stem gripper receives the downward force by its own weight, and in the taper cutting process in order to make the plug-in grafting shape it receives the rotational direction force.