A method of controlling a wheel loader, comprising: receiving signals representing a state of work currently performed by the wheel loader, from sensors (102, 143, 145, 146) installed in the wheel loader; selecting one or more signals of the received signals, the one or more signals able to be used to determine whether or not to be within a respective one of a plurality of individual load areas, wherein the individual load areas are divided according to work load which consumes a power output of an engine during a series of work states performed by the wheel loader; calculating output values representing as to whether or not to be within the respective one of the plurality of individual load areas, by using the selected signal; analyzing the output values to determine whether or not a current load state is one of a travelling work state, an excavation work state and a travelling and boom raising work state; and controlling an engine power output such that an upper limit of an output torque of the engine is limited to be smaller than a maximum output torque of the engine based on the determination result, characterized in that controlling the engine power output comprises performing a first torque control mode such that the upper limit of the output torque in the first torque control mode is be limited to a first ratio of the maximum output torque of the engine, when the current work state is determined as the travelling and boom raising work state; performing a second torque control mode such that the upper limit of the output torque in the second torque control mode is be limited to a second ratio smaller than the first ratio of the maximum output torque of the engine, when the current work state is determined as the excavation work state; and performing a third torque control mode such that the upper limit of the output torque in the third torque control mode is be limited to a third ratio smaller than the second ratio of the maximum output torque of the engine, when the current work state is determined as the travelling work state. receiving signals representing a state of work currently performed by the wheel loader, from sensors (102, 143, 145, 146) installed in the wheel loader; selecting one or more signals of the received signals, the one or more signals able to be used to determine whether or not to be within a respective one of a plurality of individual load areas, wherein the individual load areas are divided according to work load which consumes a power output of an engine during a series of work states performed by the wheel loader; calculating output values representing as to whether or not to be within the respective one of the plurality of individual load areas, by using the selected signal; analyzing the output values to determine whether or not a current load state is one of a travelling work state, an excavation work state and a travelling and boom raising work state; and controlling an engine power output such that an upper limit of an output torque of the engine is limited to be smaller than a maximum output torque of the engine based on the determination result, characterized in that controlling the engine power output comprises performing a first torque control mode such that the upper limit of the output torque in the first torque control mode is be limited to a first ratio of the maximum output torque of the engine, when the current work state is determined as the travelling and boom raising work state; performing a second torque control mode such that the upper limit of the output torque in the second torque control mode is be limited to a second ratio smaller than the first ratio of the maximum output torque of the engine, when the current work state is determined as the excavation work state; and performing a third torque control mode such that the upper limit of the output torque in the third torque control mode is be limited to a third ratio smaller than the second ratio of the maximum output torque of the engine, when the current work state is determined as the travelling work state.