[Problem] Provided is a balloon in which a rupture in a circumferential direction can be prevented from occurring, and a method of manufacturing the same.[Means for Resolution] Provided a balloon (30) which is arranged on a medical catheter, and includes a dilatable cylindrical portion (42) that is formed with a birefringent polymer material. A ratio of the number of orientation distributions calculated by dividing the number of orientation distributions of the cylindrical portion (42) in a circumferential direction by the number of orientation distributions of the cylindrical portion (42) in an axial direction is less than 2.
