This paper describes the construction of a large solar furnace of the heliostat type. A paraboloidal mirror, 10 meters in aperture and 3.1 in aperture ratio, is a mosaic composed of 181 segments that have been ground and polished accurately into portions of a paraboloid and aluminized by vacuum evaporation to form front-surface mirrors. A heliostat has a steel skeleton frame that can rotate on a circular track to change the azimuth. Seven mirror bands, each with 34 front-surface mirrors, are mounted on the frame and move synchronously to change the elevation. Following the sun image is done by both a time system and a servo-system. Some performance test results are also presented.