PROBLEM TO BE SOLVED: To provide a method for constructing a tank capable of suppressing a dike from being thicker, being performed easily and significantly shortening a construction period.SOLUTION: Provided is a method for constructing a tank constructed by building a dike on a foundation base and providing an outer tank inside the built dike, in which the dike is constructed by: assembling outer tank liner plates 10 forming the outer tank on the foundation base as an inner concrete form; assembling an outer concrete form 20 on the outside of the outer tank liner plates 10 with a predetermined interval provided therebetween; and pouring concrete 40 between the assembled outer tank liner plates 10 and the outer concrete form 20.
