Lower vehicle body structure of vehicle

In order to achieve the purpose of transmitting a rear impact load input to the front end of a side member to the rear of the side member without increasing mass and cost, the present invention describes a vehicle lower body structure comprising: a side member disposed on the outer side in the vehicle width direction at the lower part of the vehicle and having a closed cross-section formed therein that extends in the front-rear direction of the vehicle; the wheels are positioned in front of the side beams; wherein the side beam is provided with an outer side beam, and the outer side beam is provided with a front end part and a main body part located behind the front end part; in the front end part of the outer side beam, an outer side reinforcing member is jointed from the inner side or the outer side of the closed cross section, and the outer side reinforcing member has a shape along the front side surface part and the side surface part of the front end part; the front end of the main body part is opposite t