A branch tube comprising a main tube defining a continuous flow path and one or two branches connected to the main tube has a closure member connected to one end of the main tube to block the flow path thereof. The closure member is integrally molded with the main tube so that a continuous smooth flow path extends through the main tube up to the closure member and the closure member is breakable from the main tube to open the flow path. A tubular sleeve is connected to the main tube so as to surround the closure member.