The Lamb's problem for an elastic, anisotropic and homogeneous half space is solved. The source is linear and contains in the free surface of this half space. A numerical calculation based on the Cagniard de Hoop method is performed, in the case of cubic symmetry. The free surface is parallel to a plane of symmetry. In addition, the line source may be parallel, or not, to an axis of symmetry. The displacement fîeld is then calculated at any point of this half space, for various directions of this line source. This theoretical study may be applied to the generation of acoustic waves when using a laser beam focused by a cylindrical lens on a sample. The impact is then linear.