A pneumatic fender monitoring system is provided. Image data captured by using at least one of a front view imaging device that successively images an external shape in a front view of a pneumatic fender used disposed between a vessel and a vessel or a side view imaging device that successively images the external shape in a side view of the pneumatic fender is successively input into a control unit and successively displayed on a monitor, and the control unit determines, on the basis of the image data, whether an amount of deformation of the external shape of the pneumatic fender is within a preset tolerance range or outside of a preset tolerance range.