Steel pipe piles with wings are suitable for construction and environment. However, the wings at the tip of the pile installed to increase the bearing capacity disturb the surrounding ground after the penetration, which affects the frictional force on the peripheral surface of the pile and the coefficient of lateral subgrade reaction. In this study, the hardness of the surrounding ground after penetrating a steel pipe pile with wings made of flat steel plate into the sandy ground rotationally was measured by the cone penetration resistance, and the change in ground hardness before and after the pile penetration was grasped. In addition, it is considered that the steel pipe pile with wings has the effect of compacting the surrounding ground by penetrating the pile body without removing the soil. Therefore, in this study, we attempted to quantify the effect of ground disturbance for piles with wings to change the ground. hardness Moreover, we evaluated the effect of expanding the ground to harden the ground using the cavity expansion theory.