Abstract: A security door structure is affixed to an opening in a building wall exteriorly of a combination affixed glass door and sliding glass door to prevent in entrance by an intruder through the glass doors. The security door structure includes a first rigid metal frame with top and bottom rails and opposing vertical side rails and a plurality of rigid metal bars affixed between the rails. The metal bars are mounted at a predetermined distance from each other to prevent passage of a human body therebetween. The first metal frame is affixed exteriorly of the affixed glass door, and extends the same height and width as the affixed glass door. A second metal frame is pivotally mounted about a vertical axis to the first metal frame to swing between a closed position coplanar with the first metal frame and an open position pivoted exteriorly away from the coplanar position.