Lower vehicle-body structure

A lower vehicle-body structure comprising:

• a floor panel;
• a pair of side sills disposed at both ends of the floor panel in a vehicle width direction, and extending in a front-rear direction;
• at least one cross member disposed on an upper surface of the floor panel, and extending in the vehicle width direction to couple the pair of side sills together;
• and
• a reinforcement extending in the front-rear direction in each of the pair of side sills, wherein
• each reinforcement includes
• a first part disposed at a position that overlaps with the at least one cross member when a vehicle is viewed in a side view, and
• a second part disposed at a position that does not overlap with the at least one cross member when the vehicle is viewed in a side view, and
• a rigidity of the second part against a load from a vehicle-width-direction outer side is lower than a rigidity of the first part against a load from the vehicle-width-direction outer side.