Provided is a joint structure with which a pipe can be disconnected without moving the pipe in a longitudinal direction thereof, even if the pipe is not machined. A first sleeve has an inner cavity into which a pipe is inserted, and one end part of the first sleeve comes into contact with a joint body. A second sleeve has a hole into which the pipe is inserted, and one end part of the second sleeve comes into contact with the other end part of the first sleeve. A nut covers one end part of the joint body, the first sleeve, and the second sleeve, and the nut is threaded onto the joint body in a state of pressing against the surface of the second sleeve on the side opposite from the first sleeve.