A continuously variable transmission for bicycles having a transmission mechanism including a plurality of link units for converting rotary motion of an input shaft rotated by a pedal-operated crankshaft into swinging motion, and a one-way clutch for converting the swinging motion into rotary motion of an output shaft. The link units have drive links pivotally mounted on an eccentric ring which rotates in unison with the input shaft. The continuously variable transmission is disposed between a front wheel and a rear wheel of a bicycle in the longitudinal direction thereof and disposed either upwardly of a hypothetical plane which contains the axes of rotation of the front wheel and the rear wheel or upwardly of a position below and near the hypothetical plane. The transmission so configured provides better bicycle maneuverability, lower cost, while suffering almost no danger of contacting the ground.