A wheelchair tilting mechanism includes a seat support provided with pivot members and guide bars a wheel support provided with pivot pins, to which the pivot members are rotatably connected and a control unit including handlebars, actuating levers, cylinders fixedly mounted to the wheel support, and push bars separately movably received in the cylinders with an end mounted on the wheel support and the other end articulated to linking elements and fixed to the guide bars. The actuating levers are located below the handlebars to connect to the seat support via the linking elements, and fastening devices are provided at joints of the seat support and the linking elements. A control valve is provided on each of the linking elements. The tilting mechanism can be manipulated to steplessly adjust a wheelchair seat to different angular positions, allowing a patient sitting on the wheelchair to change posture.
