A high-pressure piping part includes a body structure forged in a closed space. The body structure is formed to include a main body portion formed by forward extrusion and side arm portions formed by side extrusion. The main body portion has therein a fiber flow formed along a passage, and the side arm portion has therein a fiber flow formed along the passage. Therefore, the direction in which stress is applied to the passage of the body structure by an internal pressure is approximately perpendicular to the directions of the fiber flows, thereby improving the degree of allowance of the resistance to pressure of the body structure for an injector.