Determining the hardness in the Leeb scale consists in measuring the velocity of the impact mass before and after hitting the sample. The result is the speed of the impactor shall after the rebound divided by the speed before the rebound (multiplied by 1000). The measured hardness ranges from 0 to 1000 and is largely dependent on the Young's modulus of elasticity. The article presents the Leeb hardness measurement tests of six various species of wood. The samples were machining before testing in such a way that there were places with different surface roughness on its surface. The research showed the differentiation of the hardness test results for the same tree species depending on the roughness of the surface.