A chainless bicycle for child includes a frame and a power gearing device. The frame has a seat tube between the front wheel and the rear wheel, with a passive gear axially disposed on a hub of the rear wheel. The power gearing device is disposed on the frame between the seat tube and the rear wheel. The power gearing device includes an active gear and a transmission gear meshed with the active gear. The transmission gear is meshed between the active gear and the passive gear. The power gearing device further includes a crank set disposed on two sides of the active gear for driving the active gear to rotate. Therefore, the passive gear is driven through the transmission gear to rotate in an identical direction with the active gear. Thus, the meshing structure of the present invention improves the safety of children.