We have developed a system for helping users to determine the trustworthiness of uncertain facts based on sentiment and temporal viewpoints by aggregating information from the Web. Our goal is not to determine whether uncertain facts are true or false, but to provide users with additional data on which the trustworthiness of the information can be determined. The system shows with what sentiment and in what context facts are mentioned on the Web and displays any temporal change in the fact’s popularity. Furthermore, the system extracts counter facts and analyzes them in the same way. The majority of 1000 users who evaluated our system found it to be a useful tool for helping to determine the trustworthiness of facts from various viewpoints.