A tube 4 includes a casing 1 made of a fluororesin. The casing 1 surrounds a fluid tube 3 and lid members 5 each made of a fluororesin and include a receiving portion 8 for receiving one end portion of the tube 4. At least one sealing face 10 is disposed in the receiving portion. Union nuts 6, made of a fluororesin, are fitted onto the end portion of the tube 4 and screwed to one end portion of one of the lid members 5. A sealing portion 19 is formed by fastening the union nuts 6 to the end portions of the lid members 5 to press the tube 4 from the outside of the tube 4. A device element such as a filter member 3 is placed in the casing 1.