A vehicle floor structure, in which a main structure of the vehicle floor structure is a double deck structure including two sheets of panels formed from a fiber-reinforced thermoplastic composite material; in a region including the double deck structure, each of the panels includes at least two continuous reinforcing structures having a convex open cross-sectional shape; recesses are provided in at least two places of the reinforcing structures; and the panels are joined in such a manner that the reinforcing structures of the respective panels intersect with each other, and that the recesses provided in the reinforcing structures of the respective panels are fitted to each other.