To provide a mail server and a mail processing method capable of preventing the reception of any annoying mail.

At the time of receiving an electronic mail from a transmission origin terminal 50 to a transmission destination terminal 52, a mail server 10 extracts characteristic information from the electronic mail. Then, the mail server 10 transmits the characteristic information to the transmission destination terminal 52, and receives mail processing information from the transmission destination terminal 52. Then, a mail processing means 22 processes (for example, erasures) an electronic mail corresponding to the mail processing information according to the processing contents included in the mail processing information. That is, at the time of judging that the electronic mail whose characteristic information is extracted is an annoying mail based on the characteristic information, the user of the transmission destination terminal 52 transmits the mail processing information including the erasure instruction of the electronic mail to the mail server. Thus, it is possible for the user to prevent the reception of the electronic mail judged as an annoying mail by the user himself or herself.