Abstract: A window shutter unit with a locking mechanism including a frame for mounting upon a wall in surrounding relation to a window and a panel movably supported by the frame. The panel has a vertically oriented rack and an aperture at the bottom of the rack. A rotatable and longitudinally movable shaft is positioned in a passageway through the wall beneath the window. The shaft has a pinion gear for engaging the rack. Rotational movement of the shaft selectively raises or lowers the panel within the frame. Longitudinal movement of the shaft, however, positions the pinion gear within the aperture so as to selectively lock the panel in a raised position.