To enhance efficiency of carry-in and carry-out conveyance by integrating agitation treatment for soil improvement and conveyance of sludge soil to the latter part into one unit apparatus.

A rotary shaft 20 subjected to motor drive via a chain belt 22 is arranged inside a cover case 11 including an introduction opening 14 of the sludge soil on one end part and a discharge opening 17 of improved soil on the other end part, and also an agitation projection cluster 27 arranging a spiral blade plate 24 and a plurality of non-spiral projections V are mutually disposed on this rotary shaft. The sludge soil is transferred to the latter stage by the spiral blade plate 24 and agitated by the agitation projection cluster 27 of the next stage. Apparatuses necessary to be sufficiently agitated during transfer and for soil improvement are integrated into one.