PURPOSE: To simply and surely attach a working machine such as subsoiler to a rotary tilling body fitted to various tractors.

CONSTITUTION: In this tractor working machine such as a rotary subsoiler, in which a rotary tilling body installing a rotating blade to a supporting shaft frame having cylindrical bracket attached through a connecting member to the rear of a tractor C through a connecting frame to a subsoiler comprising a frame body equipped with a means for controlling a breaking depth and angle and a breaking blade, the means for controlling breaking depth and angle is detachably attached through a fixing member to the proper position of the connecting frame.