A seat , comprising: a seat cushion unit including: a seat cushion frame ; a seat pad which lies over the seat cushion frame ; and a trim which covers the seat pad , wherein the trim includes: a trim main body which mainly covers a top surface of the seat pad ; a first trim joiner which extends from the trim main body to a backside of the seat cushion frame at the rear of the seat pad , and is fastened to the seat cushion frame ; and a second trim joiner which is connected to a back surface of the trim main body in at least one of left and right end regions of the rear of the seat cushion unit , extends to the backside of the seat cushion frame at the rear of the seat pad , and is fastened to the seat cushion frame , and wherein the seat cushion unit includes a sitting part for supporting buttocks of an occupant, and a bulge part extending in a front-rear direction on each of left and right sides of the sitting part , the trim main body has a pull-in section which extends along a boundary between the bulge part and the sitting part , and is pulled into the seat pad side, and the second trim joiner is connected to the pull-in section , and it is characteried in that the second trim joiner extends along a side pull-in section of the pull-in section that extends in the front-rear direction along the bulge part , and is connected to the side pull-in section. a seat cushion frame ; a seat pad which lies over the seat cushion frame ; and a trim which covers the seat pad , wherein the trim includes: a trim main body which mainly covers a top surface of the seat pad ; a first trim joiner which extends from the trim main body to a backside of the seat cushion frame at the rear of the seat pad , and is fastened to the seat cushion frame ; and a second trim joiner which is connected to a back surface of the trim main body in at least one of left and right end regions of the rear of the seat cushion unit , extends to the backside of the seat cushion frame at the rear of the seat pad , and is fastened to the seat cushion frame , and wherein the seat cushion unit includes a sitting part for supporting buttocks of an occupant, and a bulge part extending in a front-rear direction on each of left and right sides of the sitting part , the trim main body has a pull-in section which extends along a boundary between the bulge part and the sitting part , and is pulled into the seat pad side, and the second trim joiner is connected to the pull-in section , and it is characteried in that the second trim joiner extends along a side pull-in section of the pull-in section that extends in the front-rear direction along the bulge part , and is connected to the side pull-in section. a trim main body which mainly covers a top surface of the seat pad ; a first trim joiner which extends from the trim main body to a backside of the seat cushion frame at the rear of the seat pad , and is fastened to the seat cushion frame ; and a second trim joiner which is connected to a back surface of the trim main body in at least one of left and right end regions of the rear of the seat cushion unit , extends to the backside of the seat cushion frame at the rear of the seat pad , and is fastened to the seat cushion frame , and wherein the seat cushion unit includes a sitting part for supporting buttocks of an occupant, and a bulge part extending in a front-rear direction on each of left and right sides of the sitting part , the trim main body has a pull-in section which extends along a boundary between the bulge part and the sitting part , and is pulled into the seat pad side, and the second trim joiner is connected to the pull-in section , and it is characteried in that the second trim joiner extends along a side pull-in section of the pull-in section that extends in the front-rear direction along the bulge part , and is connected to the side pull-in section. <EOS>