Disclosed is a bicycle. A handlebar (1), a steering bar (7), a braking system, a bicycle frame, a front steering wheel (14), pedal plate driving devices, speed changing boxes (44) and rear driving wheels (45) are arranged on a bicycle body respectively, the front steering wheel (14) is mounted below the steering bar, the pedal plate driving devices and the speed changing boxes (44) are mounted on the bicycle frame, and the rear driving wheels (45) are disposed on output shafts of the speed changing boxes. The bicycle has the advantages that pedal plate driving parts (17) are added between pedal plates (22) and driving connecting rods (32), speed changing box driving parts (37) are added between the driving connecting rods (32) and driving shafts (42) of the speed changing boxes, two sets of independent pedal plate driving device driving systems are disposed under two pedal plates, and thereby, defects of a bicycle of Chinese patent number 201210084957.X can be overcome, for example, two speed-up boxes are arranged on left and right and output motive power to one shaft, twisting of output shafts can occur and one wheel can not contact with the ground during driving on uneven roads, the center of gravity of a user moves from side to side when the user treadles, instability is severe, pedaling self-moving is quite dangerous, personal safety is endangered, twisting of the output shafts can occur, the speed-up boxes can not work and the pedaling self-moving function can not be achieved.