Abstract: A nail guiding mechanism of nailing gun composed of a gun body, a nail magazine and the nail guiding mechanism. The nail guiding mechanism includes a bottom board, a middle board and a top board. The bottom board is connected between the gun body and the nail magazine. The middle board is locked on the top face of the bottom board. The middle board is formed with multiple connecting holes for multiple locating members to fit therein. The locating members protrude from the top face of the middle board. The top board is mounted on the top face of the middle board. The top board is formed with multiple locating holes respectively corresponding to the locating members. The locating members are respectively passed through the locating holes to protrude from the top board. A press shank and a latch ring are pivotally disposed on the top board. When pressing down the press shank, the latch ring is tightly latched with the locating members to fixedly connect the top board with the middle board.