A side rail formed in a split ring shape with an opening, and suitable for combining with an annular space expander to form, together with the annular space expander, a multi-piece oil ring for use in an internal combustion engine, the side rail comprising: an outer peripheral surface facing radially outward; an inner peripheral surface facing radially inward; a first axial side surface facing one side in an axial direction; and a second axial side surface facing the other side in the axial direction and being in parallel with the first axial side surface, wherein a beveled portion is provided between the outer peripheral surface and the second axial side surface; and the beveled portion is formed in a tapered surface, and has a diameter that gradually decreases from a position on the outer peripheral surface toward the second axial side surface, the position being 0.05 mm or more away from the first axial side surface toward the second axial side surface in the axial direction; characterized in that: the tapered surface has a first tapered surface portion (30a1) that is continuous to the second axial side surface at an end on the side where the second axial side surface is located, has a conical surface shape, and has an angle of inclination of 10° or more to the axial direction, and a second tapered surface portion (30a2) that is provided between the first tapered surface portion (30a1) and the outer peripheral surface, is continuous to the outer peripheral surface at an end on the side where the first axial side surface is located, has a conical surface shape, and has an angle of inclination to the axial direction smaller than that of the first tapered surface portion (30a1); the first tapered surface portion (30a1) is continuous to the second tapered surface portion (30a2), or the first tapered surface portion (30a1) and the second tapered surface portion (30a2) are smoothly connected to each other by a tapered surface subportion (30a3) in a curved shape; and the angle of the second tapered surface portion (30a2) to the axial direction is 2° or more, 12° or less, and is not 6°. an outer peripheral surface facing radially outward; an inner peripheral surface facing radially inward; a first axial side surface facing one side in an axial direction; and a second axial side surface facing the other side in the axial direction and being in parallel with the first axial side surface, wherein a beveled portion is provided between the outer peripheral surface and the second axial side surface; and the beveled portion is formed in a tapered surface, and has a diameter that gradually decreases from a position on the outer peripheral surface toward the second axial side surface, the position being 0.05 mm or more away from the first axial side surface toward the second axial side surface in the axial direction; characterized in that: the tapered surface has a first tapered surface portion (30a1) that is continuous to the second axial side surface at an end on the side where the second axial side surface is located, has a conical surface shape, and has an angle of inclination of 10° or more to the axial direction, and a second tapered surface portion (30a2) that is provided between the first tapered surface portion (30a1) and the outer peripheral surface, is continuous to the outer peripheral surface at an end on the side where the first axial side surface is located, has a conical surface shape, and has an angle of inclination to the axial direction smaller than that of the first tapered surface portion (30a1); the first tapered surface portion (30a1) is continuous to the second tapered surface portion (30a2), or the first tapered surface portion (30a1) and the second tapered surface portion (30a2) are smoothly connected to each other by a tapered surface subportion (30a3) in a curved shape; and the angle of the second tapered surface portion (30a2) to the axial direction is 2° or more, 12° or less, and is not 6°. the tapered surface has a first tapered surface portion (30a1) that is continuous to the second axial side surface at an end on the side where the second axial side surface is located, has a conical surface shape, and has an angle of inclination of 10° or more to the axial direction, and a second tapered surface portion (30a2) that is provided between the first tapered surface portion (30a1) and the outer peripheral surface, is continuous to the outer peripheral surface at an end on the side where the first axial side surface is located, has a conical surface shape, and has an angle of inclination to the axial direction smaller than that of the first tapered surface portion (30a1); the first tapered surface portion (30a1) is continuous to the second tapered surface portion (30a2), or the first tapered surface portion (30a1) and the second tapered surface portion (30a2) are smoothly connected to each other by a tapered surface subportion (30a3) in a curved shape; and the angle of the second tapered surface portion (30a2) to the axial direction is 2° or more, 12° or less, and is not 6°.