Abstract: An adjustable typewriter platform mechanism is provided for use with a desk of the type having a typewriter platform recess in the desk top. The typewriter platform mechanism includes a U-shaped base plate which is horizontally mounted at a spaced distance below the desk top. Four vertically disposed jack-screws are rotatably journalled between the base plate and the desk top for nontranslational rotation; and means is provided for simultaneously rotating all of the jack-screws.A pair of parallel spaced and horizontally disposed support-bars are mounted to respective ones of the jack-screws to receive lifting motion therefrom. Limited relative horizontal movement between the support-bars and the jack-screws is permitted in two horizontal and orthogonally intersecting axes; and means is provided for vertically guiding the support-bars in one vertical plane to minimize relative movement between the support-bars and the jack-screws in one of the aforesaid horizontal axes.