Abstract: A three-dimensional (3D) printer including a floating solution for reducing resin usage may include a main frame, a water tank disposed inside the main frame, a build platform slidable in a vertical direction along the water tank, an optical assembly disposed at an upper portion of the main frame and irradiating a laser beam to the build platform, resin contained inside the water tank, and the floating solution contained inside the water tank, wherein the floating solution is not mixed with the resin, has a higher density than the resin, and supports the resin.