Provided is a liquid supply system that can suppress a functional decline of relief valves and improve cooling efficiency. The system includes a sealed container (110), a pump (120) disposed in a cryogenic liquid (L) contained inside the sealed container (110) and driven by a linear actuator (130), a first conduit (K1) for directing the cryogenic liquid (L) pumped out by the pump (120) to a cooled device (300) provided outside the sealed container (110), a second conduit (K2) for returning the cryogenic liquid (L) from the cooled device (300) into the sealed container (110), and a relief valve (170) that is connected to the first conduit (K1) within the sealed container (110) and releases the cryogenic liquid (L) into the sealed container (110).
