A liquid supply system, comprising: a vessel configured to suck in a liquid from a first path communicating with the outside of the system and transmit the liquid that has been sucked in to a second path communicating with the outside of the system; first and second bellows (41, 42) arranged in series in an expanding/contracting direction thereof in the vessel and having first end portions (41b, 42b) respectively, which are close to each other and fixed to an inner wall of the vessel, and also having second end portions (41a, 42a) respectively, which are distant from each other and movable in the expanding/contracting direction; and a shaft which is inserted into the vessel and to which the respective second end portions (41a, 42a) of the first and second bellows (41, 42) are fixed, the shaft being reciprocally moved in the expanding/contracting direction by a drive source to expand/contract the first and second bellows (41, 42), wherein an inner space of the vessel located outside the first bellows serves as a first pump chamber provided with a first inlet port through which the liquid is sucked from the first path into the first pump chamber and a first outlet port through which the liquid that has been sucked in is transmitted from within the first pump chamber to the second path, an inner space of the vessel located outside the second bellows serves as a second pump chamber provided with a second inlet port through which the liquid is sucked from the first path into the second pump chamber and a second outlet port through which the liquid that has been sucked in is transmitted from within the second pump chamber to the second path, and a sealed space is formed inside each of the first and second bellows (41, 42), characterized in that an inner region of the first bellows and an inner region of the second bellows form one sealed space that is the sealed space. a vessel configured to suck in a liquid from a first path communicating with the outside of the system and transmit the liquid that has been sucked in to a second path communicating with the outside of the system; first and second bellows (41, 42) arranged in series in an expanding/contracting direction thereof in the vessel and having first end portions (41b, 42b) respectively, which are close to each other and fixed to an inner wall of the vessel, and also having second end portions (41a, 42a) respectively, which are distant from each other and movable in the expanding/contracting direction; and a shaft which is inserted into the vessel and to which the respective second end portions (41a, 42a) of the first and second bellows (41, 42) are fixed, the shaft being reciprocally moved in the expanding/contracting direction by a drive source to expand/contract the first and second bellows (41, 42), wherein an inner space of the vessel located outside the first bellows serves as a first pump chamber provided with a first inlet port through which the liquid is sucked from the first path into the first pump chamber and a first outlet port through which the liquid that has been sucked in is transmitted from within the first pump chamber to the second path, an inner space of the vessel located outside the second bellows serves as a second pump chamber provided with a second inlet port through which the liquid is sucked from the first path into the second pump chamber and a second outlet port through which the liquid that has been sucked in is transmitted from within the second pump chamber to the second path, and a sealed space is formed inside each of the first and second bellows (41, 42), characterized in that an inner region of the first bellows and an inner region of the second bellows form one sealed space that is the sealed space.