An automatic sending-message processing device applied to a computer network which is connected to a plurality of computer systems via communication media and capable of effecting message switching among said plurality of computer systems by use of an electronic mail system, comprising:
- inputting means for permitting a user to input control information for mail message data to be sent;
- rule storing means for storing a rule according to the language specification of a mail message and including a processing condition and a processing content identifying a process to be performed on the mail message data when the processing condition is satisfied;
- rule creating means for permitting the user to create the rule stored in said rule storing means;
- control information analyzing means for analyzing the control information of the mail message data;
- interpreting means for collating the analyzed control information with the processing condition to interpret a process to be executed;
- and
- processing means for executing a process corresponding to the process interpreted by said interpreting means on the mail message data to be sent.