A cooling liquid can be circulated in a liquid cooling system, so that a light source unit and a control unit can be forcedly cooled by the cooling liquid. Thus, a temperature increase in these components can be suppressed, thereby achieving an increase in the output power of a liquid-cooled LED lighting device. The liquid-cooled LED lighting device can include a housing, a light source unit having LEDs as light sources, a liquid cooling system, and a control unit to control the light source unit to be turned on. The liquid cooling system can include a heat receiving jacket, a radiator, a circulation pump and a fan. The light source unit and the control unit can be disposed with the heat receiving jacket of the liquid cooling system interposed therebetween. Further, one surface of the control unit can be brought in close contact with the heat receiving jacket while a heat radiation portion (e.g., fins or pins) can be provided at an other surface of the control unit.