To provide an estimation method for ground density based upon not an RI cone penetration test in which it is difficult to handle equipment, but a cone penetration test excluding sampling for measuring ground density, a management method for ground reclamation using the estimation method for ground density, a management method for ground compaction, and a management method for caisson filling.

An estimation method for ground density includes: a step S01 of measuring tip resistance at an original position by a cone penetration test; a step S02 of assuming a ground density; a step S03 of calculating a relative density; a step S04 of calculating a ground density on the basis of results of maximum and minimum density tests of soil properties which are obtained in advance and the calculated relative density; and a step S05 of comparing the assumed ground density and the calculated ground density with each other, and executing the relative density calculation step and ground density calculation step after changing the assumed ground density back in the ground density assuming step when the densities are not equal to each other or determining the ground density as an estimated ground density when the densities are equal to each other.