In recent years, many researchers investigated the structural response of pontoon type VLFS (Very Large Floating Structure). They made clear, that the waves often excite the structure outstandingly in the specific wave directions. For the design of VFLS, we have to understand sufficiently the relation between the structural response and incident wave angles. In this paper, the structural response of the VFLS, which has a rectangular plane configuration with large aspect ratio, is examined. In the results, the critical condition, that induces peak strain energy of the floating body, is presented.