1. An apparatus for detecting an inspection characteristic in an electronic mail message, the apparatus comprising: a first acquisition section for acquiring first characteristic information on the content of the electronic mail message according to the text information of the electronic mail message; a second acquisition section for acquiring second characteristic information on at least one of the sender and the addressee of the electronic mail message according to the address information of the electronic mail message; and a determination section for determining whether the electronic mail message has the inspection characteristic by comparing the first characteristic information acquired by the first acquisition section with a first condition for determining whether the electronic mail message has the inspection characteristic and by comparing the second characteristic information acquired by the second acquisition section with a second condition for determining whether the electronic mail message has the inspection characteristic.