To achieve efficient and proper transmission of an impact load from a floor frame on one side of a vehicle body to a floor frame on the other side to thereby protect a battery unit from damage, an automotive floor structure includes a first cross member upper and a first cross member lower. the first cross member upper extends in a lateral direction of the vehicle body and has ends attached to left and right side sills, respectively. The first cross member lower extends in the lateral direction below a front floor panel at a position under the first cross member upper, and has ends secured to the left and right floor frames, respectively. The first cross member upper and the first cross member lower vertically sandwich the battery unit therebetween.