There is provided a method for constructing a cylindrical tank, including the step of assembling a metal inner tank by individually and sequentially conducting, on an internal side of a PC wall, raising of an inner tank lateral plate by a jack-up unit and welding of a next-stage inner tank lateral plate onto a lower section of the raised inner tank lateral plate, further including the step of installing a guide pair configured to sandwich the raised inner tank lateral plate onto the next-stage inner tank lateral plate that is to be welded therebeneath. As a result, in the case of adopting the jack-up construction system, it is possible to prevent an inner tank lateral plate from being attached next from falling.