To reduce vibration and noise, to economically perform execution work, and to expand an improved range of liquefying strength of ground.

A solidifying body 24 for a measure against liquefaction is composed of a compacting solidifying area 24a formed in the central part and a permeating solidifying area 24b formed so as to surround the outer periphery of this compacting solidifying area 24a. In the compacting solidifying area 24a, inputted sand is compacted by horizontal directional amplitude vibration of an exciter so that this is solidified by a solidifying material. In the permeating solidifying area 24b, the solidifying material injected from an injection nozzle is permeated into the sandy ground 12 by horizontal directional amplitude vibrating force of the exciter and expansive compressive force of the compacting solidifying area 24a to solidify the solidifying material. Both these compacting solidifying area 24a and permeating solidifying area 24b are integrally created in the sandy ground 12 by solidifying the solidifying material.