The present invention relates to a mail server, a mail reception device and the like of a mail system for mutually performing transmission and reception of a mail between mobile devices or personal computers (PCs) through mediation of a mail server, which construct a mail system for significantly alleviating labor for a user on changing a mail address and for reducing network traffic. The mail server receives a change of the mail address of a user device and manages history of the mail address of the user device, receives a mail destined to a destination device from a mail transmission side device, and attaches the history of the mail address of the mail transmission side device to the received mail so as to transmit the mail having the history attached thereto to the destination device.