A front vehicle-body structure of a vehicle, the front vehicle-body structure comprising: a floor panel; a side sill extending substantially in a front-rear direction on a vehicle-width-direction outer end portion of the floor panel, wherein a cross-section of the side sill orthogonally intersecting with the front-rear direction is formed as a closed cross-section; a floor frame extending substantially in the front-rear direction on a vehicle-width-direction inner side of the side sill, wherein a cross-section of the floor frame orthogonally intersecting with the front-rear direction is formed as a closed cross-section together with the floor panel; and a cross member connecting the side sill and the floor frame to each other substantially in a vehicle width direction, wherein a cross-section of the cross member orthogonally intersecting with the vehicle width direction is formed as a closed cross-section together with the floor panel, wherein the side sill has an inner surface, which is positioned on the vehicle-width-direction inner side in the cross-section orthogonally intersecting with the front-rear direction and which extends substantially in an up-down direction, and an upper surface positioned on a top portion and extending substantially in the vehicle width direction; wherein a corner extending substantially in the front-rear direction is formed between the inner surface and the upper surface; and wherein a reinforcement member (70, 77) configured to reinforce the inner surface and the corner is provided at a position to which the cross member is connected substantially in the front-rear direction on an inner side of the side sill, wherein the reinforcement member (70, 77) includes: a joint member that is configured to define the inner side of the side sill in the front-rear direction and has a peripheral portion connected to the inner surface and the upper surface; and a corner reinforcement member substantially extending in the front-rear direction along the corner, characterized in that the corner reinforcement member is joined to the side sill together with the joint member. a floor panel; a side sill extending substantially in a front-rear direction on a vehicle-width-direction outer end portion of the floor panel, wherein a cross-section of the side sill orthogonally intersecting with the front-rear direction is formed as a closed cross-section; a floor frame extending substantially in the front-rear direction on a vehicle-width-direction inner side of the side sill, wherein a cross-section of the floor frame orthogonally intersecting with the front-rear direction is formed as a closed cross-section together with the floor panel; and a cross member connecting the side sill and the floor frame to each other substantially in a vehicle width direction, wherein a cross-section of the cross member orthogonally intersecting with the vehicle width direction is formed as a closed cross-section together with the floor panel, wherein the side sill has an inner surface, which is positioned on the vehicle-width-direction inner side in the cross-section orthogonally intersecting with the front-rear direction and which extends substantially in an up-down direction, and an upper surface positioned on a top portion and extending substantially in the vehicle width direction; wherein a corner extending substantially in the front-rear direction is formed between the inner surface and the upper surface; and wherein a reinforcement member (70, 77) configured to reinforce the inner surface and the corner is provided at a position to which the cross member is connected substantially in the front-rear direction on an inner side of the side sill, wherein the reinforcement member (70, 77) includes: a joint member that is configured to define the inner side of the side sill in the front-rear direction and has a peripheral portion connected to the inner surface and the upper surface; and a corner reinforcement member substantially extending in the front-rear direction along the corner, characterized in that the corner reinforcement member is joined to the side sill together with the joint member. a joint member that is configured to define the inner side of the side sill in the front-rear direction and has a peripheral portion connected to the inner surface and the upper surface; and a corner reinforcement member substantially extending in the front-rear direction along the corner, characterized in that the corner reinforcement member is joined to the side sill together with the joint member.