A phishing site detection device (10) extracts, from a phishing kit, a condition of access sources with which the access to a phishing site is blocked. Then, the phishing site detection device (10) accesses a phishing site constructed by the phishing kit using one or more extracted conditions of access sources, and stores an access result for each condition of access sources in an access result storage module (16). Thereafter, the phishing site detection device (10) sets a condition of access sources with which the access to the phishing site constructed by the phishing kit is blocked, accesses a website to be detected, and determines whether the website is a phishing site on the basis of the access result.