Abstract: A cylinder driving apparatus using air pressure including: a plurality of flexible tubes arranged in a case to flexibly move via high-pressure air; a connecting rod fixed at each of the flexible tubes, and which penetrates through an upper portion of the case; a crank shaft sequentially coupled to the connecting rod to rotate via the elevating movement of the connecting rod; a high pressure tank for supplying high pressure air to the flexible tubes via an air line; and a valve arranged in each of the flexible tubes to divide the space in the flexible tube into an upper section and a lower section and to open or shut airflow in the upper and lower sections.