A straddled vehicle comprising: a body frame including a head pipe, a down frame extending downward from the head pipe as the vehicle is seen from the side, and a seat frame (13L, 13R) extending rearward and upward from the down frame as the vehicle is seen from the side; a storage box supported on the seat frame (13L, 13R); a power unit pivotally supported on the seat frame (13L, 13R); a rear wheel (6, 7) supported on the power unit; wherein the seat frame (13L, 13R) includes a first portion that overlaps with the storage box as the vehicle is seen from the side, and a second portion that is located rearward of the first portion as the vehicle is seen from the side and that overlaps with the storage box as the vehicle is seen from the back, the straddled vehicle further comprising, a first bracket plate provided on the second portion of the seat frame (13L, 13R); a second bracket plate provided on the second portion of the seat frame (13L, 13R) and located inward of the first bracket plate in a vehicle width direction; a collar placed between the first bracket plate and the second bracket plate, characterized by the collar including a first cylindrical portion having a first outer diameter and a second cylindrical portion having a second outer diameter greater than the first outer diameter; and a rear cushion unit including a cylindrical upper support portion into which the first cylindrical portion of the collar is inserted and which is pivotally supported on the first cylindrical portion, and a lower support portion pivotally supported on the power unit, wherein the first bracket plate is located outward, in the vehicle width direction, of a center of the seat frame (13L, 13R) in a vertical cross section that includes a center line of the collar; at least a portion of the second bracket plate is located inward, in the vehicle width direction, of an inner end of the seat frame (13L, 13R) in the vehicle width direction in the vertical cross section that includes the center line of the collar the collar is formed so that the first cylindrical portion is located on a vertical line that passes through the center of the seat frame (13L, 13R) in the vertical cross section that includes the center line of the collar when the collar is placed so that the first cylindrical portion is located outward of the second cylindrical portion in the vehicle width direction between the first bracket plate and the second bracket plate. a body frame including a head pipe, a down frame extending downward from the head pipe as the vehicle is seen from the side, and a seat frame (13L, 13R) extending rearward and upward from the down frame as the vehicle is seen from the side; a storage box supported on the seat frame (13L, 13R); a power unit pivotally supported on the seat frame (13L, 13R); a rear wheel (6, 7) supported on the power unit; wherein the seat frame (13L, 13R) includes a first portion that overlaps with the storage box as the vehicle is seen from the side, and a second portion that is located rearward of the first portion as the vehicle is seen from the side and that overlaps with the storage box as the vehicle is seen from the back, the straddled vehicle further comprising, a first bracket plate provided on the second portion of the seat frame (13L, 13R); a second bracket plate provided on the second portion of the seat frame (13L, 13R) and located inward of the first bracket plate in a vehicle width direction; a collar placed between the first bracket plate and the second bracket plate, characterized by the collar including a first cylindrical portion having a first outer diameter and a second cylindrical portion having a second outer diameter greater than the first outer diameter; and a rear cushion unit including a cylindrical upper support portion into which the first cylindrical portion of the collar is inserted and which is pivotally supported on the first cylindrical portion, and a lower support portion pivotally supported on the power unit, wherein the first bracket plate is located outward, in the vehicle width direction, of a center of the seat frame (13L, 13R) in a vertical cross section that includes a center line of the collar; at least a portion of the second bracket plate is located inward, in the vehicle width direction, of an inner end of the seat frame (13L, 13R) in the vehicle width direction in the vertical cross section that includes the center line of the collar the collar is formed so that the first cylindrical portion is located on a vertical line that passes through the center of the seat frame (13L, 13R) in the vertical cross section that includes the center line of the collar when the collar is placed so that the first cylindrical portion is located outward of the second cylindrical portion in the vehicle width direction between the first bracket plate and the second bracket plate.