The utility model discloses a forklift truck and a fork arm of the forklift truck. The fork arm comprises a support plate and a fork arm body. The support plate is arranged on the fork arm body through a tripping type connecting device. The tripping type connecting device comprises a marble fixing device, a marble, a first marble hole and a second marble hole, wherein the marble fixing device is arranged on the inner wall of the fork arm body, one wall face of the fork arm body is provided with a first marble hole, the marble is fixed on the marble fixing device and is exposed out of the first marble hole, and the support plate is provided with a second marble hole which is used in cooperation with the marble. In this way, when the fork arm is used, the support plate is fixed on the fork arm body through the tripping type connecting device; the fork arm body is moved backwards, the support plate and the fork arm body are disconnected under the stopping action of bending plates, the support plate and a current transformer placed on the support plate stay in situ, the current transformer is directly located on the two bending plates and can be installed, and therefore the current transformer can be installed in place without being dragged.