We present a new anisotropic driving force model to compute the anisotropy of the mobility and impact ionization rate in TCAD simulations of SiC devices. We derive the model from the relationship between the mobility, driving force, and carrier heating, where the obtained driving force along the c-axis and that perpendicular to the c-axis depend on the gradient of the quasi-Fermi potential and the mobility anisotropy factor (the mobility ratio along the perpendicular direction to that along the c-axis). Since mobility also depends on the driving force, we solve for the mobility anisotropy factor to determine the anisotropic mobility and driving force together. We also propose a new interpolation scheme to consider the anisotropy of the impact ionization rate using the derived anisotropic driving force. We compare the present model with the existing models in the commercial simulator and demonstrate its applicability to the simulation of a 4H-SiC vertical power MOSFET device.