To provide a method for rotatively press-fitting a cylindrical casing by a shaft excavator, which can carry out quick excavation of a shaft.

The shaft excavator includes a machine body 1, and functions to grasp the cylindrical casing 100 for embedding, which is erectly set on the ground G, and to press-fit the same into the ground by a press-fitting mechanism 9, a grasping mechanism 19, and a rotation driving mechanism 25. The press- fitting mechanism 9 is connected to a pressurizing frame 18, and bears the same above a reaction bearing frame 8 of the machine body 1 in a vertically movable manner. The grasping mechanism 19 for grasping the cylindrical casing 100, is borne above the pressurizing frame 18 in an expandable/contractible manner. The rotation driving mechanism 25 rotates the cylindrical casing 100. Then, a ground portion inside the cylindrical casing 100 is excavated by the shaft excavator, and ring weights 31 each equipped with a positioning means, are successively accumulated on the casing 100 according to increase in press- fitting resistance of the cylindrical casing 100, to thereby add a press-fitting load to the casing 100.