The effect of mechanical treatment of the Z-surface of a lithium niobate single crystal on the properties of a pyroelectric X-ray source was experimentally investigated. In the experiment, the properties of the source were measured with a roughness of the Z-surface of the crystal in the range 3-8 mu m. As a result, the effect of the surface roughness of the pyroelectric crystal on the process of X-ray generation with a pyroelectric effect is shown.