This is an open trial, involving a total of 24 subjects. Subjects who give consent will be screened and those who meet trial criteria will receive CHONDRON (Autologous cultured Chondrocyte) by transplant. During the trial period, subjects must follow the instructions given by principal investigator. Subjects will make 8* hospital visits on a regular basis inclusive of hospitalization. During these visits subjects will be examined. For the evaluation of safety and efficacy of CHONDRON, examination with doctors, blood samples, x-ray, MRI tests, observation with the naked eyes and arthroscopy will be performed. *If tissue samples can be collected at screening visit, there will be only 7 visits.