A connection port 31 includes a cylindrical outer port 42 to which downstream piping 30b (discharge-side piping) is connected; an inner port 43 to which upstream piping 30a (supply-side piping) is connected, and which is provided in the outer port; and a lid member 44 which closes the inner port as well as the outer port. The inner port is provided so as to extend through the outer port from the outside of the outer port, and a heater H is provided on a portion of the inner port projecting outside the outer port. When the lid member is in a closed state, the inner port is heated with the heater to sterilize the portion of the inner port exposed to the outside, thus enabling the connection port to be cleaned at a higher level.