A fully automatic system for the seedling transplantation process was investigated as the first study of the automation for the plant tissue cultivation, is a representative technique in biotechnology. As a result, the transplantation robot called 'Mericlone robot' drived by the shape memory alloy actuator, the plant-antenna sensor for detecting a seedling position and the seedling growth state discriminator employing the color sensors were conceived and developed. Furthermore a microcomputer-controlled seedling transplantation system was developed by integrating all the above prototype devices. This system yields success in soft grasping, planting, and unplanting the seedlings of diameter 0.5 mm and length 20 mm, at 15 mm spacing into the culture medium without damage to the seedlings.