A work vehicle comprising: a main hydraulic pump which is driven by an engine; a lift arm cylinder which extends and retracts by a delivery pressure discharged from the main hydraulic pump; a control valve which switches a moving direction of the lift arm cylinder; a loading hydraulic circuit which includes at least the main hydraulic pump, the lift arm cylinder, and the control valve; an auxiliary hydraulic pump which is provided separately from the main hydraulic pump and driven by the engine; a negative parking brake device which releases a braking state by supply of pressure oil discharged from the auxiliary hydraulic pump; and a parking brake releasing hydraulic circuit (B2, B21-B25) which supplies the pressure oil discharged from the auxiliary hydraulic pump to the parking brake device, characterized in that the vehicle has: a loading operation hydraulic circuit located upstream of the parking brake releasing hydraulic circuit (B2, B21-B25); an emergency flow path for supplying the pressure oil discharged from the auxiliary hydraulic pump to the parking brake device through the loading operation hydraulic circuit in an emergency; and a valve unit (81, 83, 84) which is located in the emergency flow path and can be switched to a communicating position to communicate the emergency flow path or a shutoff position to shut off the emergency flow path, wherein if pressure in the parking brake releasing hydraulic circuit (B2, B21-B25) is lower than a brake release pressure to release the braking state of the parking brake device, the valve unit (81, 83, 84) is switched to the communicating position. a main hydraulic pump which is driven by an engine; a lift arm cylinder which extends and retracts by a delivery pressure discharged from the main hydraulic pump; a control valve which switches a moving direction of the lift arm cylinder; a loading hydraulic circuit which includes at least the main hydraulic pump, the lift arm cylinder, and the control valve; an auxiliary hydraulic pump which is provided separately from the main hydraulic pump and driven by the engine; a negative parking brake device which releases a braking state by supply of pressure oil discharged from the auxiliary hydraulic pump; and a parking brake releasing hydraulic circuit (B2, B21-B25) which supplies the pressure oil discharged from the auxiliary hydraulic pump to the parking brake device, characterized in that the vehicle has: a loading operation hydraulic circuit located upstream of the parking brake releasing hydraulic circuit (B2, B21-B25); an emergency flow path for supplying the pressure oil discharged from the auxiliary hydraulic pump to the parking brake device through the loading operation hydraulic circuit in an emergency; and a valve unit (81, 83, 84) which is located in the emergency flow path and can be switched to a communicating position to communicate the emergency flow path or a shutoff position to shut off the emergency flow path, wherein if pressure in the parking brake releasing hydraulic circuit (B2, B21-B25) is lower than a brake release pressure to release the braking state of the parking brake device, the valve unit (81, 83, 84) is switched to the communicating position. a loading operation hydraulic circuit located upstream of the parking brake releasing hydraulic circuit (B2, B21-B25); an emergency flow path for supplying the pressure oil discharged from the auxiliary hydraulic pump to the parking brake device through the loading operation hydraulic circuit in an emergency; and a valve unit (81, 83, 84) which is located in the emergency flow path and can be switched to a communicating position to communicate the emergency flow path or a shutoff position to shut off the emergency flow path, wherein if pressure in the parking brake releasing hydraulic circuit (B2, B21-B25) is lower than a brake release pressure to release the braking state of the parking brake device, the valve unit (81, 83, 84) is switched to the communicating position.