To facilitate adjustment of an interval between a side part of a door side end of a steel door and a door frame and soften a stopper in the case of opening and shutting by making a side part of the door side end of the steel door of an elastic material.
Both front and rear sides of a steel door 1 are formed of steel plates 2, and a side part 3 of a door side end is made of silicone rubber. The side part 3 is held between the ends bending the steel plates 2 at constricted parts 4 lengthwise of both sides and is fixed. After that, the door side is contacted with a silicone rubber stopper section 6 projected to a jamb 5. According to the constitution, an interval between the stopper section 6 and jamb in the case of hanging and mounting is controlled by cutting the side part 3, and impact in the case it is contacted with the jamb stopper section can be lightened.