Abstract: When both the IABP and the PCPS are used, they exhibit an excellent circulation assisting effect. In this case, however, sequela such as hypoxic encephalopathy may well occur after the heart failure is remedied. The invention provides an intraaortic balloon catheter capable of preventing such sequela. The balloon catheter of the invention includes a catheter main body part which is to be inserted into an aorta, and a balloon section formed on an outer peripheral portion of the catheter main body, to be inserted into the aorta together with the main body, and to be expandable and contractible in the aorta under the control of the IABP. An end portion of the catheter main body functions as an introductory portion of the catheter, and has a blood feed hole formed therein for introducing, into an artery such as the aortic arch, arterial blood of high oxygen concentration fed from a circulation assisting unit such as the PCPS.