To estimate the viscous resistance of an enlarged ship with high accuracy.

In this viscous resistance estimating method for the enlarged ship, viscous resistance is estimated by a shape influence coefficient estimating regression expression created using a parameter indicating the flow field characteristic of a ship form obtained from the integrated value, at a bow part and a stern part, of the variation of a pressure coefficient obtained by calculating double model flow around a hull, a parameter indicating the increase of resistance caused by secondary flow at a stern, and a geometrical shape parameter of the ship form.