PURPOSE: To enable the execution of work in a perfect soil discharged soil free state, by improving an execution device for foundation piles, equipped with an auger head forming a pressed soil edge on the peripheral edge of a screw blade and with a cylindrical casing having the auger head and revolving it, and improving the operation method for the device.

CONSTITUTION: Press compact shoes 4a-4d are fixedly installed on the periphery of the lower edge part of a casing 3, and a plurality of projecting stripes 5a-5l are formed on the periphery of the casing 3. A plurality of projecting stripes are arranged, keeping a certain angle for the center axis of the casing. The press compact shoe spreads the inner peripheral surface of a hole which an auger head 2 spreads, and prevents the destruction of the inner peripheral surface of the hole through press compaction, and a perfect discharged-soil free state can be generated.