Abstract: An intra-aortic balloon pump apparatus includes a first catheter one end of which is secured to a connector having a gas supply port, a balloon one end of which is secured to the distal end of the first catheter, a central tubular member the distal end of which projects from the distal end of the first catheter and to which the distal end of the balloon is fixedly secured, a second catheter freely insertable into the central tubular member and having a distal end provided with an arterial pressure transduceer, and a second connector to which the other end of the second catheter is secured for feeding a signal from the pressure transducer to the outside of the apparatus. After the balloon, central tubular member and first catheter are placed into the aorta, the second catheter having the pressure transducer at its distal end is inserted through the interior of the central tubular member into the aorta.