Abstract: A pair of frames are slidably interfitted on a common slide axis. Safety bars placed normal to the slide axis and alternately opposite sides of the slide axis, are fixed in the frames in sliding noninterference and for halving space between bars when frames are slidably coincident. Frames are pivotally fixed in the lintel or upper half of a building window casing for pivoting outwardly. A locking device, mounted in a window casing and controllable by anyone in the building and remote from the casing, locks the frames slidably and pivotally coincident in the casing as closely spaced window safety bars, and similarly unlocks the frames to pivot them outwardly clear of the window sill for slidable extension downwardly as an exterior fire escape ladder with double spaced rungs and angled handrails for standing entry on the ladder from the window sill. Bar stops fixed to opposite ends of the respective frames prevent separation of the slidably interfitting frames.