A bottom tube clamp (8) comprises a tube pressing part (82) and tube bearing part (89), which oppose one another so that a tube (33) passes therebetween in the radial direction； and which are configured so as to, by moving the tube pressing part (82) toward the tube bearing part (89), press a portion of the tube (33) between the tube pressing part (82) and the tube bearing part (89) and stop the flow of fluid inside the tube (33). A projection (82a) is formed on at least one of the tube pressing part (82) and tube bearing part (89), protruding toward the other. The projection (82a) is positioned on the side from which the tube (33) disposed between the tube pressing part (82) and tube bearing part (89) is removed.
