A method of evaporating liquid in a liquid evaporating system having heat exchangers, evaporators, and steam reheaters, includes: preheating condensed water in the heat exchangers; distilling in the evaporators the condensed water from the heat exchangers, wherein the evaporators each has a horizontal plane evaporating chamber at an upper side thereof and a horizontal plane steam heating chamber at a lower side thereof, wherein heating steam is provided from an external boiler to the heating chamber; exchanging heat between the evaporating chamber and the heating chamber using a heat exchange boundary face formed in a concavo-convex shape, wherein the heat exchange boundary face is formed of a metal plate; and reheating in the steam reheaters the steam from the respective evaporators, wherein the reheaters each are coupled to a subsequent one of the heating chambers to serve as a heating source of the subsequent heating chamber.