A folding bicycle comprises a support assembly pivotably connected to a portion of a head tube below a lower enlargement above a front wheel; and a rear wheel assembly comprising a front end pivotably connected to a quick release slidable along the head tube, an intermediate enhancement including a padded cross bar interconnected its right and left portions, an intermediate point pivotably connected to an intermediate point of the support assembly, and two auxiliary wheels fixedly connected to both ends of a hub of a rear wheel as kickstand. Unfastening and sliding the quick release the quick release upward until being stopped by a stop fixedly connected to handlebars, and fastening the quick release will fold the bicycle. Alternatively, unfastening and sliding the quick release downward until being stopped by the enlargement, and fastening the quick release will unfold the bicycle.