Nailing gun

A nailing gun comprising:

• a frame;
• a flywheel mounted on said frame and driven by a motor;
• a hammer unit having a swing arm, and a hammer rod slidably mounted on said swing arm, said swing arm having a first end pivoted to said frame, and a second end that is movable between a first position proximate to said flywheel and a second position distal from said flywheel, said hammer rod being driven by said flywheel to hit a nail when said swing arm is at the first position;
• a spring plate fixed to said frame and having a spring end portion resiliently supporting said second end of said swing arm on said frame;
• a stop member disposed movably in said frame near said second end of said swing arm to limit said spring end portion and said second end of said swing arm from moving relative to said frame;
• and
• a safety unit including a safety member disposed on said frame, said safety member, when subjected to an external pressure exerted by an object to be nailed, pushing said stop member away from said second end of said swing arm so that said second end of said swing arm is permitted to move together with said spring end portion to the first position;
• wherein said spring end portion stably retains said second end of said swing arm at the second position when said safety member is not subjected to the external force and does not push said stop member.