Recently, an excavated soil-recycling machine has been receiving considerable attention because excavated soils can be recycled at the construction sites. Some researches have already carried out to investigate the mixing behavior of excavated soils and additives in this machine. However, the optimum operating condition is not still clear. Therefore, the purpose of this study is to investigate the effect of soil properties on the mixing performance of excavated soils and additives in the soil-recycling machine. In this experiment, the soil discharge amount and agitation torque were measured by using sandy soils and adhesive clay soils. The soil discharge amount were high when the water content of the soil was low, however, it decreased with increasing the water content and it showed a minimum in the vicinity of the liquid limit. When the water content of the soil is beyond the liquid limit, the soil discharge amount increased. On the other hand, the agitating torque showed the opposite tendency. The agitating torque showed a maximum in the vicinity of the liquid limit and it decreased rapidly with increasing the water content.