The present invention discloses a pumping device of a shoe 100 includes a cushion body (110) formed inside a sole of the shoe (110) and having front and back air chambers (120 and 130) formed therein in such a manner as to be disposed at the front and back portions thereof; an automatic pump (140) mounted adjacent to the back air chamber (130) in such a manner as to communicate with the back air chamber (130) and having a height (H2) higher than a height (H1) of the back air chamber (130); a suction valve (150) and a check valve (160) mounted at the front and back sides of the automatic pump (140); and a pressure adjusting valve (170) formed at a connecting valve (125) for connecting the back air chamber (130) with the front air chamber (120).