A dehydration system has improved membrane performance. The dehydration system includes a dehydrating apparatus 1 comprising, in a dehydrating apparatus body, a water separation membrane module in which a water separation membrane having at least one flow path extending in the up and down direction to cause a liquid 50 to pass through is provided with a liquid inlet at the bottom thereof and a liquid outlet at the top thereof; and a shell 11 defined by the outer surface of the water separation membrane module and the inner wall of the dehydrating apparatus body, wherein water in the liquid permeates the water separation membrane while the liquid rises in the water separation membrane, and moves in the shell, whereby the liquid is dehydrated; a pressure reducing device 13 for reducing the pressure of the shell 11; a pressure device for pressurizing the liquid before the liquid is fed to the water separation membrane module; and a heating device for heating the pressurized liquid.