Most studies on responses of a very large floating structure have been investigated in regular waves. So, estimation methods were validated in a frequency domain. However, it is important for validation with better accuracy and understanding the characteristics of responses to measure responses of VLFS in irregular waves. And, they must be measured exactly in order to compare with corresponding theoretical results in time domain. Authors measured some responses by model tests, which can be compared with time series of theoretical results of responses in two-directional irregular waves. The present paper shows the measurement method of the responses of an elastic body, and proposes some results of the responses in not only uni-directional irregular waves but also two-directional irregular waves. Then, angles of incident waves were not only head or beam sea conditions but also oblique waves.