A vehicle body structure, comprising: a vehicle body floor having a bottom surface part; a floor tunnel swelling upward from the bottom surface part in the vehicle body floor and extending along a vehicle longitudinal direction; and a floor cross member provided on the bottom surface part so as to extend outside in a vehicle width direction from the floor tunnel and form a ridgeline (L1, L2) extending in the vehicle width direction with an upper surface part of the floor cross member, wherein at least one of the vehicle body floor and the floor cross member is provided with a predetermined fixed position at which a mount member, which is configured to support a power transmission mechanism to be arranged in the floor tunnel, is to be fixed from below, wherein the fixed position is arranged so as to overlap the floor cross member in the vehicle longitudinal direction, is arranged outside of the floor tunnel in the vehicle width direction, and is arranged upward of the bottom surface part in a vehicle vertical direction, wherein the vehicle body floor includes a raised part to which the mount member is to be fixed, wherein the raised part is configured to be stepped up from the bottom surface part toward a lower edge part of the floor tunnel in the vehicle width direction, wherein an inner end part of the floor cross member in the vehicle width direction is arranged to overlap an upper side of the raised part at which the mount member is to be fixed to the vehicle body floor and the floor cross member, and wherein the fixed position of the mount member corresponding to the raised part is at approximately the same height as the ridgeline (L1, L2). a vehicle body floor having a bottom surface part; a floor tunnel swelling upward from the bottom surface part in the vehicle body floor and extending along a vehicle longitudinal direction; and a floor cross member provided on the bottom surface part so as to extend outside in a vehicle width direction from the floor tunnel and form a ridgeline (L1, L2) extending in the vehicle width direction with an upper surface part of the floor cross member, wherein at least one of the vehicle body floor and the floor cross member is provided with a predetermined fixed position at which a mount member, which is configured to support a power transmission mechanism to be arranged in the floor tunnel, is to be fixed from below, wherein the fixed position is arranged so as to overlap the floor cross member in the vehicle longitudinal direction, is arranged outside of the floor tunnel in the vehicle width direction, and is arranged upward of the bottom surface part in a vehicle vertical direction, wherein the vehicle body floor includes a raised part to which the mount member is to be fixed, wherein the raised part is configured to be stepped up from the bottom surface part toward a lower edge part of the floor tunnel in the vehicle width direction, wherein an inner end part of the floor cross member in the vehicle width direction is arranged to overlap an upper side of the raised part at which the mount member is to be fixed to the vehicle body floor and the floor cross member, and wherein the fixed position of the mount member corresponding to the raised part is at approximately the same height as the ridgeline (L1, L2).