A cart comprises a body structure and at least one wheel connecting structure. The body structure comprises a support shaft, a first frame member and a second frame member. Both the first and second frame members are disposed on the support shaft. The wheel connecting structure is disposed on one end of the support shaft and comprises a driving assembly, a rotating assembly, a linking assembly, and an energy assembly. The driving assembly is connected to the first frame member. One end of the rotating assembly is disposed in correspondence with the one end of the support shaft, and the other end of the rotating assembly is mounted on a wheel member. The linking assembly is disposed between the driving assembly and the rotating assembly. The linking assembly comprises a pushing unit, which is pivotally connected to the rotating assembly. The energy assembly is connected to the linking assembly.