Technologies to ensure information transfer security are being developed, but risks remain when people enter highly confidential information like personal data into systems in public areas. To provide complete security, we need both communication security and physical security. Accordingly, we conducted a fundamental study of environments designed for secure handling of personal information in public spaces. We studied people's personal space when they are using a PC in a public work environment. First, we conducted an experiment to evaluate the degree of reassurance a user feels while inputting personal information into a PC in a public work environment. Using the results, we grouped the degrees of reassurance into four levels of "personal space in communicating information", each for a different type of information. That is, different types of information had different safe sizes. This confirms results from our previous research.