Provided are a harmful site collection device and method for determining a harmful site by analyzing a connection between harmful sites. The harmful site collection device includes a harmful site database configured to store a URL of a harmful site; a web page collection and extraction unit configured to collect a web page indicated by the URL of the harmful site and extract a linked URL; and a harmful site connection analysis unit configured to calculate a connection with other web pages referenced within a web page of the linked URL to determine whether the web page is a harmful site. Accordingly, the harmful site collection device can determine a harmful site more easily only with information regarding the URL linked to the web page.