Extreme ultraviolet light source device

The extreme ultraviolet light source device is provided with: a light source unit that generates plasma that emits extreme ultraviolet light; a vacuum chamber disposed between a utilization device that utilizes the extreme ultraviolet light and the light source unit; a fragment trap which is disposed inside the vacuum chamber and which shifts the traveling direction of fragments emitted from the plasma toward the utilization device from the light direction of the extreme ultraviolet light; a heat-insulating plate structure disposed inside the vacuum chamber and disposed between the plasma and the debris trap; and a cooling mechanism that cools the heat-insulating plate structure. The heat-insulating plate structure has a first heat-insulating plate and a second heat-insulating plate that overlaps the first heat-insulating plate with a gap therebetween. The second heat shield is disposed between the first heat shield and the plasma. The first heat insulation plate is cooled by the cooling mechanism. 极紫外光光源装置具备