A support method of decommissioning work of nuclear power plants using Augmented Reality was proposed and a prototype system was developed. Then, using the prototype system, the proposed method was evaluated. Three professionals used the prototype system along with a scenario which dismantles an ion tower, and then questionnaire and interview investigation was conducted. As the results, it was found that the proposed method that records the cutting parts on the CAD data using a stylus pen was easy and effective compared with the legacy recording method using paper instruction sheet, however a new tablet PC that has a larger screen with lighter weight is required in order to apply the proposed method to the actual decommissioning work.