PROBLEM TO BE SOLVED: To provide a guide catheter allowing more certain maintenance of a locking state of the tip of the guide catheter to a coronary artery.SOLUTION: A guide catheter 100 includes: a guide catheter body 120 to be inserted into a blood vessel and a balloon 140 inflating to the centrifugal direction of the guide catheter body 120 by being injected with a pressurized fluid, and abutting on the inner wall of the blood vessel. The balloon 140 is provided with a portion having an inflation rate smaller than a portion abutting on the inner wall of the blood vessel upon the inflation. Thereby, because a distal part of the guide catheter body 120 is supported immovably to the inner wall of the blood vessel by the inflation of the newly provided balloon 140, a locking state of the tip of the guide catheter 100 to a coronary artery can be more certainly maintained. Furthermore, because an interval occurs between the peripheral face of the balloon 140 and the inner wall of the blood vessel, the shutoff of blood flowing inside the blood vessel of the coronary artery can be prevented.
