To provide a loosened soil processing method and a loosened soil processing device capable of complying with the high quality, high productivity, workability, economy, versatility or the like of a loosened object.

Each of cutting blades 41 that are radially arranged in a plurality of upper and lower steps in a processing container 21 and are attached to a vertical rotational axis 35 is horizontally rotated at a high speed to generate a horizontal cutting energy. Then, an improved soil 71 is horizontally cut with the blades 41 generating the horizontal cutting energy by the high-speed horizontal rotation to produce the loosened soil with water in spaces of soil particles held from the injection of the soil into the container 21 from an inlet 22 to the gravity fall of the improved soil in lump at an outlet 23.