To provide a solid-liquid separation system in which a stable operation can be continuously conducted and the introduction cost and the running cost can be suppressed, in cases where moisture or oil are separated from a substance containing moisture or oil by using changes in phase of a working fluid having a nature of dissolving moisture or oil in a liquid phase. Provided is a solid-liquid separation system in which a working fluid that dissolves moisture or oil in a liquid phase is liquefied and brought into contact with a solid substance to thereby allow the working fluid to contain moisture or oil that has been contained in the solid substance, and then the working fluid is vaporized to precipitate the moisture or oil, characterized in that the solid-liquid separation system is provided with a fluid circuit in which a high-temperature-side heat exchanger that vaporizes the working fluid by a refrigerant, a low-temperature-side heat exchanger that liquefies the working fluid by the refrigerant are connected to circulate the working fluid, and a refrigerating cycle in which a compressor, a condenser that exchanges heat with a heat source other than the working fluid, the high-temperature-side heat exchanger, an expansion mechanism, and the low-temperature-side heat exchanger are sequentially connected to circulate the refrigerant, and that the solid-liquid separation system includes a recovery operation mode in which the working fluid in a filling tank is vaporized, besides the solid-liquid separation. For performing the recovery operation mode, a second expansion mechanism is provided between the condenser and the high-temperature-side heat exchanger. The system is also characterized in that the fluid circuit is provided with a heating unit that does not use the refrigerant as a heat source.