The purpose of this study is to develop the measures of the perceived risks involved in e-commerce. To do this, we first review the literature and examine the sub-constructs of the perceived risks. The risks classified are economic risk, product performance risk, social risk, technology/time loss risk, and privacy risk. Based on these findings, we identify the appropriate items for assessing these various risks. Then, we evaluate, basically using a structural equation model, the important several attributes of the measurs such as various validities and reliability. This study finally provides the rigorously tested measuring instruments of the construct of the perceived risks.