A balloon controller for an endoscope apparatus, which expands or shrinks a first balloon attached to an insertion portion of an endoscope by supplying fluid to the first balloon or drawing fluid from the first balloon, and which expands or shrinks a second balloon attached to an insertion assist implement for guiding the insertion portion when the insertion portion is inserted, by supplying fluid to the second balloon or drawing fluid from the second balloon, the balloon controller including a display device which displays an image expressing the states of expansion and shrinkage of the first balloon and the second balloon.