Abstract: A thin layer liquid film type evaporator including a cylindrical heating column, a heater for heating the cylindrical heating column, a liquid film forming plate disposed in the cylindrical heating column, a baffle also disposed in the cylindrical heating column and a feed nozzle disposed at the upper center of the cylindrical heating column. The liquid film forming plate has an outer diameter such that a clearance may be formed between the outer edge thereof and the inner circumferential surface of the heating column and that the liquid may flow through the clearance. Thus, a thin layer liquid film type evaporator which has a simple mechanism and can exhibit excellent evaporation efficiency can be provided.