An inner catheter is disclosed, which includes an elongated inner shaft to be inserted into a blood vessel; and a hub connected to a proximal end of the inner shaft. The inner shaft forms a first shape at least a part of which is wound in a state where the inner shaft is suspended in a gravity direction, and forms a second shape at least a part of which is wound and in which a length of the inner shaft along the gravity direction is shorter than a length of the inner shaft along the gravity direction in the first shape in a state where the inner shaft is placed on a flat reference plane perpendicular to the gravity direction.