Apparatus for driving fasteners comprising a barrel, a fastener guide which retreats as the apparatus is pressed against something, a feed magazine, receiving a loader of fasteners, and pressing-against-something safety means designed to allow a fastener to be driven only after the fastener guide has retreated. There is a safety shoe designed to, when there is no fastener in the barrel, be moved into a safe position and prevent the retreat of the fastener guide, comprising a tell-tale of the safe position of the safety shoe.