The invention provides a pneumatic nailing gun, and belongs to the technical field of nailing guns. The problem of how to reduce abrasion of a locking piece and a
firing pin is solved. According to the pneumatic nailing gun, a lifting part comprises a rotating shaft and a
rotating disc for driving a
firing pin to move, the rotating shaft and the
rotating disc are connected and arranged in a mounting cylinder, a rotating piece is arranged on the rotating shaft or the
rotating disc, a first pawl is rotationally arranged on the rotating piece, a gear ring matched with the first pawl is further arranged in the mounting cylinder, and first ratchets are arranged on the inner side face of the gear ring; the first pawl is located on the inner side of the gear ring and engaged with the first
ratchet to limit rotation of the rotating disc. By means of the structure, lifting, locking, unlocking and nailing of the
firing pin can be achieved without arranging an additional locking structure on the firing pin, abrasion of the firing pin is reduced, the rotating disc, the rotating shaft, the first pawl used for locking the firing pin and the gear ring are all arranged in the mounting cylinder, and therefore the nailing gun is more compact in structure.