A storage container includes a storing section including a storage space and an inflow port, and a water sealing section. The storing section includes an inflow section connectable to a tube and a volume changing section capable of changing the volume of the storage space. The volume changing section is deformed to increase the volume of the storage space when pressure in the storage space is about to rise to be equal to or higher than a reference pressure set in advance and is deformed to reduce the volume of the storage space when the pressure in the storage space is about to drop to be lower than the reference pressure.
