A fluid plug unit includes a cylinder connected to a first conduit and a second conduit such that the first conduit and the second conduit communicate with each other, and a piston configured execute switching between a first position where leakage of a fluid in the first conduit to an outside is suppressed, and a second position where the fluid is sucked by a suction device via the first conduit and the second conduit. The fluid plug unit includes a first passage configured to communicate with the first conduit and the second conduit when the piston is disposed in the first position, and to shut off communication with the first conduit when the piston is disposed in the second position, and a second passage configured to shut off communication with the first conduit when the piston is disposed in the first position, and to communicate with the first conduit and the second conduit when the piston is disposed in the second position.
