To provide an electrolyte circulation type battery system that prevents self-discharge.

An electrolyte circulation type battery system includes: a battery cell; electrolyte tanks in which respective electrolytes are stored; circulation routes that form respective electrolyte flow paths between the battery cell and the respective electrolyte tanks; and circulation pumps that allow the respective electrolytes to circulate through the respective circulation routes. The system has: a battery unit 2 in which the battery cell, which ranges from one to thirty in number, is connected in series; and a booster means (booster transformer means 50) that transforms a voltage of the battery unit 2 to an AC voltage higher than the voltage of the unit 2 and outputs the AC voltage.