A stone slicer of slicing rough stone into stone plates having a predetermined thickness, which can improve productivity by reducing consumption of the rough stone by minimizing the thickness of a cut portion cut by a saw blade, and can reduce the treatment cost of sludge generated when the stone is sliced and prevent pollution due to the generated sludge. The stone slicer includes a base (10) on which stone is placed, four columns (22, 24, 26, 28) vertically installed at four edges of the base (10), a pair of a pair of platforms (30, 30’) installed left and right so as to be capable of simultaneously elevating along either side of the columns (22, 24, 26, 28), platform driving means (40, 40’) for elevating the platforms (30, 30’), one or more endless track type belt saws (70) each having opposite ends mounted in parallel with driving pulleys (50) and driven pulleys (60) provided at the platforms (30, 30’), and belt saw driving means (80) for driving the belt saws (70) to slice the stone placed on the base (10) to a predetermined thickness while rotating along an endless track by rotating the driving pulleys (50).