The present invention relates to a door opening or closing tool for a retort sterilization apparatus. The door opening or closing tool can open a door without manually unscrewing a clamp and automatically seal the closed door without manually tightening the clamp again, thereby quickly opening and closing the door and keeping the space utilization performance regardless of the opening and closing of the door of a sterilizing tank. According to an embodiment of the present invention, the door opening or closing tool for a retort sterilization apparatus opens or closes the door of the sterilization tank which is in a horizontal cylinder shape and supplies and circulates high-temperature and high-pressure steam for sterilization and discharging of retort products. The door opening or closing tool includes: a first protrusion unit protruding to the outside in a radial direction from a side of the edge o a door； a door rotating shaft which is coupled to the first protrusion unit, is extended in the longitudinal direction of the sterilization tank, and includes a fixing link aligning in the protrusion direction of the first protrusion unit in a vertical direction； a second protrusion unit protruding from a side of the edge of the sterilization tank； an opening and closing cylinder which has an end coupled to the second protrusion unit by hinges, has the other end coupled to the fixing link of the door rotating shaft by hinges, rotates the door in an upward direction when stretching the length to open the door, and rotates the door in a downward direction to close the door when reducing the length； a first semicircular clamp fixed on a flange formed on an edge of the sterilization tank； and a second semicircular clamp fixed on another flange formed on an edge of the door and forms a circular champ with the first semicircular clamp when closing the door.본 발명은 클램프를 수동으로 조임해제시키지 않고도 도어의 개방이 가능하고 클램프를 수동으로 다시 조이지 않고도 도어의 폐쇄 직후에 자동으로 기밀이 유지될 수 있어 도어의 개폐가 신속용이하게 이루어질 수 있으며 멸균탱크에
