Abstract: A convertible sofa bed mechanism is disclosed which is adapted to be mounted in a frame and includes a foldable bed frame having at least a leg and a head section articulated together for folding within the frame. The head section is rigid and is adapted to move between a first storage and a second sleep position parallel to its first position. The linkage mechanism mounts the bed frame in the sofa frame and operates to move the bed frame between folded and unfolded positions. The linkage mechanism includes a mobile link which moves at least in pivotal rotation during movement of the head section between its first and second positions. A headboard is pivotally mounted on the head section and extends across the frame.