A work vehicle, comprising: an engine ; a working device that includes a work tool and a lift arm ; a hydraulic cylinder that is for driving the working device ; a main hydraulic pump that is driven by the engine and discharges pressure oil that is for driving the hydraulic cylinder ; an operation device that operates the hydraulic cylinder ; an accessory pump that is driven by the engine and discharges pressure oil that is for driving an auxiliary machine , a confluence switching valve that merges pressure oil discharged from the accessory pump with pressure oil discharged from the main hydraulic pump , a rotation speed detection device that detects rotation speed of the engine characterised by an atmospheric pressure detection device that detects an atmospheric pressure, an outside air temperature detection device that detects an outside air temperature, and a control device that controls the confluence switching valve , the control device , in case the atmospheric pressure or air density of outside air is lower than a predetermined value, executing confluence limitation control of reducing a confluence flow amount at the confluence switching valve compared to the time in case the atmospheric pressure or the air density of the outside air is higher than the predetermined value, and canceling the confluence limitation control in case rotation speed of the engine becomes higher than a predetermined rotation speed value during the confluence limitation control, and the rotation speed value is higher as the atmospheric pressure or the air density of the outside air is lower, wherein the control device includes an air density calculation section that calculates the air density of the outside air based on the atmospheric pressure detected by the atmospheric pressure detection device and the outside air temperature detected by the outside air temperature detection device . an engine ; a working device that includes a work tool and a lift arm ; a hydraulic cylinder that is for driving the working device ; a main hydraulic pump that is driven by the engine and discharges pressure oil that is for driving the hydraulic cylinder ; an operation device that operates the hydraulic cylinder ; an accessory pump that is driven by the engine and discharges pressure oil that is for driving an auxiliary machine , a confluence switching valve that merges pressure oil discharged from the accessory pump with pressure oil discharged from the main hydraulic pump , a rotation speed detection device that detects rotation speed of the engine characterised by an atmospheric pressure detection device that detects an atmospheric pressure, an outside air temperature detection device that detects an outside air temperature, and a control device that controls the confluence switching valve , the control device , in case the atmospheric pressure or air density of outside air is lower than a predetermined value, executing confluence limitation control of reducing a confluence flow amount at the confluence switching valve compared to the time in case the atmospheric pressure or the air density of the outside air is higher than the predetermined value, and canceling the confluence limitation control in case rotation speed of the engine becomes higher than a predetermined rotation speed value during the confluence limitation control, and the rotation speed value is higher as the atmospheric pressure or the air density of the outside air is lower, wherein the control device includes an air density calculation section that calculates the air density of the outside air based on the atmospheric pressure detected by the atmospheric pressure detection device and the outside air temperature detected by the outside air temperature detection device . <EOS>