A balloon controller for an endoscope apparatus which enables an operator to correctly and immediately grasp circumstances relating to an abnormal condition at the time of occurrence of the abnormal condition. The balloon controller controls expansion and shrinkage of each of a first balloon attached to an insertion portion of an endoscope and a second balloon attached to an insertion assist implement, by supplying air to the balloon or drawing air from the balloon. Pressure indicating portions on which the values of pressures in the first and second balloons are displayed are provided in a front surface of a main body of the balloon controller. When an abnormal condition occurs, an error code and the pressure values are alternately displayed on the pressure indicating portions.