To provide a method for effectively preventing liquefaction of the ground upon occurrence of an earthquake, which is inexpensive and which can have a short construction period.

Several tension members 1 are extended downward from the lower part 2a of a structure 2 built on the ground G1. The tension members 1 are anchored with their lower end parts in the bottom parts of insertion holes by means of a solidifier 11, and are engaged on their upper end parts 1a with nuts 12. By fastening the nuts 12, an tensile axial force is exerted to the tension members 1 so as to increase the constraint pressure of the ground G1 between the each adjacent tension members 1, thereby it is possible to enhance liquefaction-resistant strength.