Abstract: The present invention relates to a medical instrument, and more particularly, to a balloon infuser. The balloon infuser includes an upper cover (10) in which a scale mark (13) including linear scales is displayed, a lower cover (20) fixed to a lower side of the upper cover (10), a flexible expandable member (70) located inside the upper cover (10) and in which contents are accommodated, and an elevation part (30) elevated according to an expansion degree of the expandable member (70) and having a scale indication line (34) on one surface thereof, the scale indication line (34) indicating the scale mark (13).