A variable ratio transmission mechanism is used in an automobile. The automobile includes first and second steering shafts extending along a first direction. The variable ratio transmission mechanism includes a securing unit connected to the first steering shaft, a connecting unit connected to the second steering shaft, a motor connected to the securing unit and including a revolving shaft that extends rotatably along a second direction different from the first direction, and a transmitting unit including a worm gear that is provided on the connecting unit and a worm that is provided on the revolving shaft and that engages and is angularly-slidable relative to the worm gear.