A security device for buildings comprises a barricade including a metal frame with a metal gridwork anchored thereto and extending across and covering the interior frame opening. The frame is configured to fit within a doorway or window opening. At least one positioning bar is disposed on one side of the frame and extends outward therefrom to beyond the frame perimeter, said positioning bar configured for placing into a receiving slot formed in the interior perimeter of the doorway or window opening. A locking bar is slidably journalled within guide track openings formed in guide tabs which are secured to the barricade. Said locking bar includes at least one perimeter locking end for slidable entry into a receiving slot formed in the interior perimeter of the doorway or window opening. Opposite said perimeter locking end on the locking bar is an interior locking end which releasably interlocks with the mounting plate when the perimeter locking end is seated within said receiving slot to thereby retain the barricade in a secured position.