A pressure regulating unit capable of suitably regulating pressure to be applied to liquid, a liquid supplying apparatus, and a liquid ejecting apparatus are provided. An ink communication path allows an ink introducing chamber communicating with an ink inlet and a pressure chamber communicating with an ink outlet to communicate with each other. A part of the pressure chamber is formed of a flexible film. A valve including a valve body and a valve seat adjusts an opening degree of the ink communication path. An urging member applies, to the valve, a first urging force acting in a direction in which the ink communication path is closed. An urging member applies, to the film, a second urging force that is greater than the first urging force and acts in a displacement direction in which the volume of the pressure chamber is reduced.