PURPOSE: To efficiently form anchor bodies by a method in which a base seat is fixed to the tip of a hollow tension member, an outlet port for cement milk is provided, and a pile body having a spiral blade on its periphery is provided projectionally forwards from the base seat.

CONSTITUTION: An earth anchor is penetrated into the ground through a retaining wall 21 while being turned to form a larger-diameter pit 23 than a tension member 9 behind the base seat 4. When cement milk 24 is injected into the hollow portion 1a from the outer end of the tension member body 1, the cement milk 24 coming out of the outlet port 8 is packed into the surrounding space of the tension member 9. A part of the cement milk 24 coming out of the outlet port 8 goes into the inlet port 12 side of the pile body 10 and is injected from the outlet port 13.