A robot system was developed to pick desired colony. This robot system consisted of an image acquisition process which acquires the image information of colony, an illumination device which irradiates the object once when it gets the image of it, a picking head, a replicating head, a bed for fixing well-plates, and a sterilization device of sterilizing pin stained with colony. Picking pins were washed in an ultrasonic wave washing for takes ten seconds. Picking pins were dipped for sterilizing in alcohol for ten seconds. The time for resterilizing picking pins in a heater was five seconds. This performance test resulted 100% success rate for both the colony picking and the colony replication process. Considering the procedure in which 8 pins were smeared by colony, picked on a well plate, and sterilized as one cycle, the system could carry out one cycle in 110 seconds. It took about 138 minutes to pick around 600 colonies.