A swingable and speedable freewheeled vehicle includes a swingable device installed between a frame and each rear wheel. The swingable device has a guiding track fixed to a seated member, a spindle pivoted on said seated member, and a sliding assembly for sliding along the guiding track. Thereby, while driving the freewheeled vehicle via swinging, a sliding stem of the sliding assembly would slide along the guiding track and subject to an inertial force. Accordingly, a distance between the ground and the frame would be varied commensurately with the freewheeled vehicle moving along with the inertia force during the sliding so as to readily and speedily motivate the freewheeled vehicle forwards.