To overcome the problem such that conventional mailing of electronic data via the Internet cannot have warranted the sure arrival of the data to an opposite party because the data are transmitted but the result of the arrival is not checked.

The Internet monitoring method monitors electronic data transmitted from a sender to a recipient via the Internet by a selected path on the Internet designated in advance by the sender and informs the sender about whether or not the electronic data being a supervisory object pass through the designated selected path and about its passing time.