A vehicle seat comprising: a fastened member comprising a fastened member-side base section formed from metal, and a fastened member-side reinforcement section formed from fiber reinforced plastic, laminated in a sheet thickness direction over the whole of the fastened member-side base section so as to reinforce the fastened member-side base section; and a fastening member (40, 50) comprising a fastening member-side base section (42, 52) formed from metal, and a fastening member-side reinforcement section (44, 54) formed from FRP, laminated in a sheet thickness direction over the whole of the fastening member-side base section (42, 52) so as to reinforce the fastening member-side base section (42, 52); wherein the fastening member (40, 50) is fastened to the fastened member by bringing the fastening member-side base section (42, 52) into contact with the fastened member-side base section, wherein an exposed portion (26, 32, 48, 64) is provided at the fastened member-side reinforcement section and/or the fastening member-side reinforcement section (44, 54) so as to expose a portion of the fastened member-side base section and/or the fastening member-side base section (42, 52), characterized in that a projection portion (28, 46, 66, 72) is provided at the fastened member-side base section and/or the fastening member-side base section (42, 52), and the projection portion (28, 46, 66, 72) projects outward the exposed portion (26, 32, 48, 64) side and is disposed in the exposed portion (26, 32, 48, 64), such that the projection portion (28, 46, 66, 72) contacts the fastened member-side base section and/or the fastening member-side base section (42, 52), and the fastened member-side base section and the fastening member-side base section (42, 52) are fastened at a location at which the projection portion (28, 46, 66, 72) contacts the fastened member-side base section and/or the fastening member-side base section (42, 52). a fastened member comprising a fastened member-side base section formed from metal, and a fastened member-side reinforcement section formed from fiber reinforced plastic, laminated in a sheet thickness direction over the whole of the fastened member-side base section so as to reinforce the fastened member-side base section; and a fastening member (40, 50) comprising a fastening member-side base section (42, 52) formed from metal, and a fastening member-side reinforcement section (44, 54) formed from FRP, laminated in a sheet thickness direction over the whole of the fastening member-side base section (42, 52) so as to reinforce the fastening member-side base section (42, 52); wherein the fastening member (40, 50) is fastened to the fastened member by bringing the fastening member-side base section (42, 52) into contact with the fastened member-side base section, wherein an exposed portion (26, 32, 48, 64) is provided at the fastened member-side reinforcement section and/or the fastening member-side reinforcement section (44, 54) so as to expose a portion of the fastened member-side base section and/or the fastening member-side base section (42, 52), characterized in that a projection portion (28, 46, 66, 72) is provided at the fastened member-side base section and/or the fastening member-side base section (42, 52), and the projection portion (28, 46, 66, 72) projects outward the exposed portion (26, 32, 48, 64) side and is disposed in the exposed portion (26, 32, 48, 64), such that the projection portion (28, 46, 66, 72) contacts the fastened member-side base section and/or the fastening member-side base section (42, 52), and the fastened member-side base section and the fastening member-side base section (42, 52) are fastened at a location at which the projection portion (28, 46, 66, 72) contacts the fastened member-side base section and/or the fastening member-side base section (42, 52).