Most of previous studies on the problem of sea level rise focused on prediction of sea level rise and measurement of physical damage cost, but did not consider uncertainty and psychological damage on the risk of storm surge disaster. Moreover, relationship between household's damage cost by sea level rise and benefit by countermeasures against sea level rise was not clear in those studies.The purpose of this study is to define and measure household's da mage cost and benefit under uncertainty by applying concept of equivalent variation to expected utility level of household's, to clarify that relationship.