A sole member capable of securely suppressing the advancement of a gonarthrosis by fitting to the heel part bottom face of a shoe bottom to gently generate a torque while securely relieving impact force when a heel part touches the ground and also enabling comfortable walking without a sense of incongruity even if a healthy person uses it to prevent the gonarthrosis. The sole member comprises a base (4) and a plurality of ribs (5) with elasticity. For use, the base (4) is fixed to the heel part (3a) bottom face of the shoe bottom (3). While tilting in a same direction, the ribs (5) are projected and radially extended from the base (4) in a ground-contact direction, and disposed on the base at prescribed intervals in the circumferential direction. Since the ribs (5) are formed in a shape curved in a radial direction, they are gradually tilted while deforming by a body weight pressure when they touch the ground to relieve the impact force and gently generate the torque in a horizontal direction relative to a ground-contact surface.