PURPOSE: To perform linear drilling by rotatably and fixably providing a casing outwardly fitted on an excavating shaft, and connecting and holding the casing and the excavating shaft at the preset interval.

CONSTITUTION: A casing 3 outwardly fitted on the excavating shaft 2 of a rotating device 1 is provided rotatably and fixably by a separate casing rotating device 4. The casing 3 and the excavating shaft 2 or casings 3 are connected and held by a connecting holder 5 at the preset interval. A stirring means 6 is fitted at the lower end section of the casing 3 to thoroughly stir the excavated sediment and a hardening agent such as cement milk. A soil cement pile uniformly mixed with the excavated sediment and the hardening agent such as cement milk can be constructed, and linear drilling can be performed.