The invention provides a jetting and agitating construction method and a jetting and agitating device for a
pile formed by reusing, as a construction material, a
sludge mixed with a medium for improving a ground such as a hardener after excluding
solid matters with large grain sizes without treating the
sludge as an
industrial waste or a general surplus soil. In this jetting and agitating construction method, a
compressed air and a water are jetted from a third jetting part while rotating and pulling up a multi-tube rod with a plurality of jetting parts from the ground to
cut the improved area of the ground in a cylindrical shape by jetting, the
cut sludge is discharged to the surface of the ground through an excavated hole, the medium for improving the ground is jetted from the
nozzle of the first jetting part, and a reaction material solidifying the medium for improving the ground is jetted from the
nozzle of the second jetting part to construct the
pile with a specified
diameter. The
solid matters with the specified grain size or larger are separably removed from the sludge discharged to the surface of the ground, mixed with the medium for improving the ground to form a mixed medium, force-fed by a force-
feed pump, and jetted from the first jetting part.