To provide an unevenness treatment system of a slate material which forms various wave-like stripes without changing a natural hue and a texture of the slate material, improves a life and strength without causing a crack, prevents a waste of the material, prevents a bend of the slate material during unevenness treatment, freely makes the unevenness having a predetermined depth, and enhances productivity.

The unevenness treatment system has a transfer part transferring the slate material to be surface-treated, an apparatus main body arranged on the upper part of the transfer part, a high pressure water injecting device mounted on one side of the apparatus main body facing the slate material and having at least one injecting nozzle injecting the high pressure water toward the slate material, a drive part making the high pressure water injecting device approach to or separate from the slate material so that the unevenness of a predetermined shape showing directivity is formed on the surface of the slate material by the high pressure water.