To perform peening on a narrow part and its rear surface incapable of directly peening a shot due to the shape of an object at a sufficient peening strength.

This shot peening method, which is performed for an internal circumferential surface of a continuous groove 4 being continuously recessed into a groove shape, or a workpiece surface (s) incapable of directly impacting the shot 6, includes a first step of disposing a reflecting member reflecting the shot at a prescribed angle in the bottom of the continuous groove, a second step of peening the shot from the side of an opening 4a of the continuous groove and peening the workpiece surface by the shot reflected by the reflecting member, and a third step of moving the reflecting member along the continuous groove and peening it in order. A practical component to be applied with the shot peening method is the internal circumferential surface of a disk post 4' for fixing a blade 3 formed in a spool type turbine disk 2'.