The invention discloses a labeling device for a security inspection machine. The labeling device includes a detecting device, a control device and an executive device, and the detecting device includes an image collecting module and an image transport module; the control device includes a processor, a display module for showing real-time image information and a labeling order input module; and theexecutive device includes a support, a rolling mechanism which is installed on the support and a pressing-down mechanism which is used for pressing labels in the rolling mechanism down to baggage. According to the labeling device for the security inspection machine, the baggage contained with forbidden objects can be marked during security check, so that staff can pick up the baggage contained with the forbidden objects which passes through a security inspection machine without stopping the security inspection machine, not only is the security check efficiency improved, but also the phenomenon of crowded passengers can be prevented at security check exit.