A pair of left and right rockers are arranged along a vehicle longitudinal direction at lower portions of two vehicle lateral direction ends of a body. A floor cross-member is provided at each of two vehicle lateral direction end portions of a cross member, which is arranged along the vehicle lateral direction at a lower portion of the body. A lower side joining flange of each rocker and a vehicle lateral direction outer side end portion of a bottom wall portion of each floor cross-member are joined together by a mount bracket. With the rocker and/or the floor cross-member, the mount bracket forms a closed cavity, of which a vehicle lateral direction outer side portion extends beneath a rocker inner. A nut is provided in the closed cavity for joining the body with a body mount, which is fixed to a chassis frame.