This study proposes a method to facilitate the identification of human error in calling out such qualitative risk assessment in Gas plants. The main idea of this method is based on the scheme of existing qualitative risk assesment technique. The guidewords and tabular worksheet are suggested to be compatible in human error analysis. By using this method developed, the maintenance procedure of Governor system in gas valve station was analyzed to discover the human error in maintenance tasks. As a consequence, certain human errors were identified and the suggested approches proved to be adequate technique for the human error analysis.