In a discharge tube, a conductive ferrule is provided on an end portion of a glass tube. The ferrule includes a body that is to be mounted to the outer circumference of the glass tube and has a contact portion to be electrically conductively fixed to a relay connector (or a bearing device). Further included is a conductive portion that extends from the body so as to have elastic contact with an outer lead. The outer lead will not be under load due to the weight of the discharge tube, but the conductive portion solely has elastic contact therewith. Thus, stress concentration on the outer lead can be prevented.