This is the latest footage in the series of executions carried out by the sunni radical organisation. Child militants of ISIS are termed as "Cubs of Caliphate".
The man was killed for spying in Al Jazeera - a likely reference to the Arabian Peninsula, rather than the news broadcaster.
Early last month ISIS released an execution video from inside Palmyra, showing 25 child executioners lining up regime soldiers in a Roman amphitheatre and shooting them in the head.
The group used to capture its brutality in the camera to terrorise people. The group blew up a child as part of a training exercise in Iraq's violent Diyala Province, North East of Baghdad in July.
ISIS has inspired fear and horror with its rule over territory in Syria and Iraq, where mass killings and brutal executions have become its hallmarks. The group controls about 50 per cent of Syria's territory and perhaps a third of Iraq.