[Problem] There are provided a balloon catheter, by which it is possible to improve operability of a guide wire and it is possible to prevent various problems which can arise in a case of using a metal reinforcing member from arising, and a medical elongated body, by which it is possible to decrease sliding resistance of a medical device that is inserted through a lumen and it is possible to prevent various problems which can arise in a case of using a metal reinforcing member from arising in advance. [Means for Resolution] An inner tube 100 provided in a balloon catheter 1 has a tubular body 110 made of a first resin and a reinforcing member 120 disposed on an inner side of the tubular body. The reinforcing member is configured of a linear body 121 including a second resin. The inner tube has a first region 103 including a distal portion provided with a distal opening portion 103a and a second region 105 that is disposed to be closer to a proximal side than the first region. The linear body projects from an inner surface 111 of the tubular body in the second region and less projects from the inner surface of the tubular body in the first region than in the second region.
