We report a study of thermally induced depolarisation of a laser beam in single cubic syngony crystals of 432,
, and m3m symmetry groups with an anisotropic elastic stiffness tensor. For active elements in the form of a long rod and a thin disk with radial cooling under uniform volume pumping, we investigate the effect of anisotropy of elastic properties on the dependence of the degree of depolarisation in the crystal on the orientation of the crystallographic axes, as well as on the position of the critical orientation in the crystallographic coordinate system.