To perform marking on any lens so as to always have certain visibility.

A marking device includes a laser marker 17 for carrying out laser marking at a target marking position of a lens 12. The marking device includes a measuring device 18 for measuring a distance between the target marking position and the laser marker 17. The marking device includes a distance adjustment device 19 for changing an interval between the lens 12 and the laser marker 17 so that the distance measured by the measuring device 18 corresponds to a marking distance L set in advance. The marking device includes a conveyance device 13 for conveying the lens 12 so that the target marking position can face the laser marker 17 or the measuring device 18.