A mail monitoring system comprises a mail communications apparatus and a control server that controls a log relating to operation of the apparatus. The apparatus includes a detector that detects transmission of an e-mail, a log generation unit that determines whether to generate a transmission log based on a set policy, and generates the transmission log, a mail creating unit that determines whether to store mail information based on the set policy, and generates the mail information, and a transmitter that transmits the mail information and the transmission log to the server, and transmits the e-mail to a mail server designated as a transmission destination of the e-mail. The server includes a receiver that receives the transmission log and the mail information and a storage unit that stores therein the transmission log and the mail information when the receiver receives the transmission log and the mail information.