Abstract: Previous to the sending of an electronic mail, an attached file verifying unit retrieves a mail text to retrieve the presence or absence of an attachment representation indicative of the existence of an attached file, and if the attached representation has been retrieved, it issues for display a warning message urging the sender to verify the forget-to-attach. Furthermore, the attached file verifying unit compares the estimated number of attached files based on a number of attached files representation in the mail text with the actual number of attached files existing in the electronic mail, and if the actual number of the attached files is less than the estimated number of the attached files, it issues a warning message indicative of a lack of the attached files. In addition, the attached file verifying unit compares a file name in the mail text with a file name in the attached file, and if the two are not coincident with each other, it issues a warning message indicative of attachment of an erroneous file.