There are provided a phishing-prevention method capable of preventing phishing-related accidents from which an Internet user suffers and storage medium storing a computer program source for executing the method. When a user attempts an access to a specific website through an e-mail and a web browser or inputs his/her own personal information directly in e-mail or the like to transmit the related information to outside, the website to be accessed or an Internet address of a specific server is analyzed in order to warn the user in advance so that the user can select whether to actually access thereto, prior to accessing to the website, if it is in danger. When the user attempts an access to a website similar to a famous or known website address, the method of the present invention warns the user of a possibility that will be a phishing website so that the user can select whether to actually access thereto. When the user makes use of the function of inputting his/her personal information directly in e-mail to transmit the related information directly to a specific server, the method of the present invention transfers a warning therefor to the user so that the user can select whether to actually transmit the related information. In making all the warnings and the user's selections, familiar and easily-expressed information associated with the website is provided to the user for his/her correct judgment.