[PROBLEMS] To provide an intra-aortic balloon pumping set for conducting the IABP therapy, capable to reduce a burden on a patient and to inflate and deflate with a high response. [MEANS FOR SOLVING PROBLEMS] An intra-aortic balloon pumping set having an introducer and an intra-aortic balloon catheter. The introducer has an inner diameter at the distant end of A mm and a tubular member having a diameter of B mm or less can be inserted thereinto but a tubular member having a diameter exceeding B mm cannot be inserted. The length in the axial direction of the introducer is C mm. The outer tube of the balloon catheter has an outer diameter of less than A mm. It is composed of a first part having a length of 1 to 400 mm, a second part which is connected to the proximal end side of the first part and has an outer diameter of A to B mm and a length of (C-10) to (C+30) mm, and a third part which is connected to the proximal end side of the second part and has an outer diameter exceeding B mm.
