A work vehicle that includes: a working device having a work tool and a lift arm; wheels; an engine as a driving source; a torque converter for transmitting power of the engine to the wheels through working fluid; a lock-up clutch capable of switching an input member and an output member of the torque converter between an engagement state and a non-engagement state; a power supply unit for supplying electric power to a control device; and an indicating device for directing activation of the power supply unit and starting of the engine, comprising: a hydraulic source; a control valve that controls a flow of hydraulic oil discharged from the hydraulic source, and switches the lock-up clutch to either state of the engagement state or the non-engagement state; and an engine starting device for starting the engine when the starting of the engine is directed by the indicating device, characterized in that the control device has: a low-temperature state determination unit that when the activation of the power supply unit is directed by the indicating device and the power supply unit is activated, determines whether a temperature state of the working fluid of the torque converter is a low-temperature state; and a clutch control unit that when it is determined by the low-temperature state determination unit that the temperature state of the working fluid is not the low-temperature state, controls the control valve in order to switch the lock-up clutch to the non-engagement state, and that when it is determined by the low-temperature state determination unit that the temperature state of the working fluid is the low-temperature state, controls the control valve in order to switch the lock-up clutch to the engagement state. a working device having a work tool and a lift arm; wheels; an engine as a driving source; a torque converter for transmitting power of the engine to the wheels through working fluid; a lock-up clutch capable of switching an input member and an output member of the torque converter between an engagement state and a non-engagement state; a power supply unit for supplying electric power to a control device; and an indicating device for directing activation of the power supply unit and starting of the engine, comprising: a hydraulic source; a control valve that controls a flow of hydraulic oil discharged from the hydraulic source, and switches the lock-up clutch to either state of the engagement state or the non-engagement state; and an engine starting device for starting the engine when the starting of the engine is directed by the indicating device, characterized in that the control device has: a low-temperature state determination unit that when the activation of the power supply unit is directed by the indicating device and the power supply unit is activated, determines whether a temperature state of the working fluid of the torque converter is a low-temperature state; and a clutch control unit that when it is determined by the low-temperature state determination unit that the temperature state of the working fluid is not the low-temperature state, controls the control valve in order to switch the lock-up clutch to the non-engagement state, and that when it is determined by the low-temperature state determination unit that the temperature state of the working fluid is the low-temperature state, controls the control valve in order to switch the lock-up clutch to the engagement state. a low-temperature state determination unit that when the activation of the power supply unit is directed by the indicating device and the power supply unit is activated, determines whether a temperature state of the working fluid of the torque converter is a low-temperature state; and a clutch control unit that when it is determined by the low-temperature state determination unit that the temperature state of the working fluid is not the low-temperature state, controls the control valve in order to switch the lock-up clutch to the non-engagement state, and that when it is determined by the low-temperature state determination unit that the temperature state of the working fluid is the low-temperature state, controls the control valve in order to switch the lock-up clutch to the engagement state.