NOVELTY - A desalination system comprises de-mineralizer (25) which has reverse osmosis membrane that filters the supplied salt water and isolates into freshwater and high concentration salt water, discharge port for freshwater (16) and discharge port for high concentration salt water (17), osmotic pressure electric power generating apparatus (30) which is a semi-permeable membrane (32) which partitions off high concentration side flow path and low concentration side flow path, water supply part (23), high concentration salt water supply part (24), and 1st pump (12a).    USE - A desalination system (claimed).    ADVANTAGE - Desalination system is low cost and can desalinate salt water stably.    DETAILED DESCRIPTION - A desalination system comprises de-mineralizer (25) which has reverse osmosis membrane that filters the supplied salt water and isolates into freshwater and high concentration salt water, discharge port for freshwater (16) which discharges freshwater and discharge port for high concentration salt water (17) which discharges high concentration salt water, osmotic pressure electric power generating apparatus (30) which is a semi-permeable membrane (32) which partitions off high concentration side flow path and low concentration side flow path, is electric-power-generated when electric power generation amount fell and is provided so that electric power might be supplied to 1st pump, water supply part (23) which supplies freshwater or salt water to low concentration side flow path, high concentration salt water supply part (24) which supplies high concentration salt water discharged from discharge port for high concentration salt water by high concentration side flow path, and 1st pump (12a) which is provided so that salt water may be pressurized by electric power supplied from electric power supplied from electric power generating apparatus which uses natural energy.    DESCRIPTION OF DRAWING(S) - The drawing shows a schematic block diagram of the desalination system. (Drawing includes non-English language text).    1st pump (12a)    Discharge port for freshwater (16)    Discharge port for high concentration salt water (17)    Water supply part (23)    High concentration salt water supply part (24)    De-mineralizer (25)    Osmotic pressure electric power generating apparatus (30)    Semi-permeable membrane (32)