A catheter that includes a tubular inner layer, a first reinforcing body that is wound around an outside in a radial direction of the inner layer, a second reinforcing body that is wound around the outside in the radial direction of the first reinforcing body, and an outer layer that covers the inner layer, the first reinforcing body, and the second reinforcing body, and the inner layer has a reduced diameter portion that is reduced in diameter from a proximal end side of the catheter toward a distal end side of the catheter on an inner peripheral surface of the inner layer, and a thickness of the outer layer between the first reinforcing body and the second reinforcing body is increased, at least partially from the proximal end side toward the distal end side, in the radial direction of the reduced diameter portion.