Floor panel structure and vehicle body provided therewith

In a floor panel structure of a vehicle body in which a floor of an automotive vehicle is formed by a floor panel 2 coupled to a plurality of frame members 22, 27, 36 extending in substantially longitudinal and width directions of the vehicle, there are provided a panel area S2 formed by being enclosed at least by the frame members 22, 27, 36, a heavy-weight area 82 located at a substantially central portion of the panel area S2, and a peripheral area 84 located substantially around the heavy-weight area 82, wherein the heavy-weight area 82 is configured so as to be heavier than the peripheral area 84. Accordingly, the vibration energy transmitted from the frame members to the floor panel can be reduced and thereby the acoustic emission generated from the floor panel can be reduced.