A forklift comprising an apparatus for controlling the forklift, the apparatus comprising: a setting unit which sets reference weight of a cargo; an input unit into which weight of an actual cargo is detected and input, and a cargo movement direction, in which the actual cargo slides and moves on a fork, is input; a determining unit which determines whether the cargo is overloaded by comparing the weight of the actual cargo with the reference weight of the cargo, and determines an inward/outward cargo movement direction; and a processing unit which gives a control command to a vehicle control unit or a hydraulic system so that an inclination of a mast is adjusted when the determining unit determines that the cargo is overloaded and determines that the movement direction of the cargo is a direction far from a main body of the forklift, a brake or a brake control unit which is installed in a travelling system of the forklift and brakes the forklift; and a power train or a power train control unit which is installed in a power train system of the forklift to transmit power to the traveling system, wherein the setting unit further sets a reference travelling speed, a current travelling speed of the forklift is further input into the input unit, the determining unit further determines whether the forklift speeds by comparing the current travelling speed with the reference travelling speed, and when the determining unit determines that the forklift speeds and the movement direction of the cargo is determined as the direction far from the main body of the forklift, the processing unit gives a control command so that the brake or the brake control unit is controlled to decrease the travelling speed of the forklift or stop the forklift, or gives a control command so that the power train or the power train control unit is operated to control an output size of the power. a setting unit which sets reference weight of a cargo; an input unit into which weight of an actual cargo is detected and input, and a cargo movement direction, in which the actual cargo slides and moves on a fork, is input; a determining unit which determines whether the cargo is overloaded by comparing the weight of the actual cargo with the reference weight of the cargo, and determines an inward/outward cargo movement direction; and a processing unit which gives a control command to a vehicle control unit or a hydraulic system so that an inclination of a mast is adjusted when the determining unit determines that the cargo is overloaded and determines that the movement direction of the cargo is a direction far from a main body of the forklift, a brake or a brake control unit which is installed in a travelling system of the forklift and brakes the forklift; and a power train or a power train control unit which is installed in a power train system of the forklift to transmit power to the traveling system, wherein the setting unit further sets a reference travelling speed, a current travelling speed of the forklift is further input into the input unit, the determining unit further determines whether the forklift speeds by comparing the current travelling speed with the reference travelling speed, and when the determining unit determines that the forklift speeds and the movement direction of the cargo is determined as the direction far from the main body of the forklift, the processing unit gives a control command so that the brake or the brake control unit is controlled to decrease the travelling speed of the forklift or stop the forklift, or gives a control command so that the power train or the power train control unit is operated to control an output size of the power.