A balloon pumping method of inflating and deflating a balloon includes the steps of setting a pressure in the balloon at a first pressure value, which is higher than a minimum pressure value and is substantially equal to or lower than a maximum pressure value, when the balloon is shifted from a deflated condition to an inflated condition, and setting the pressure in the balloon at a second pressure value, which is substantially equal to or higher than the minimum pressure value and lower than the first pressure value, when the balloon is estimated to have completely inflated at the first pressure value.
