A continuously variable transmission comprises an input shaft and an output shaft, a drive wheel, a toothed wheel or a chain wheel, an endless sleeve, a ring wheel, at least one linking member, wedge teeth or a chain, wherein the drive wheel is provided with an annular recess in which a plurality of reversal wedge teeth run, and the wedge teeth are connected with a head portion of the linking member connected with the ring wheel, the spread of axles between the drive wheel and the ring wheel is adjusted via the swinging of the endless sleeve; and with the aid of the locking and releasing operations of the wedge teeth, the linking members are urged to drive the ring wheel, whereby changing the input and output transmission ratio. The continuously variable transmission can be used in a bicycle, wherein the spread of axles between the ring wheel and the drive wheel can be adjusted by regulating a wire, and the magnitude of speed variation is not restricted, the variation range is large, and the power could be synchronously input during the speed variation.