Internal stresses of diamond films deposited by hot filament chemical vapor deposition (HFCVD) were measured by micro-Raman spectroscopy. The internal stresses estimated by Line shifts of micro-Raman spectroscopy can be classified into the compressive thermal and tensile intrinsic stresses. The study of Raman spectroscopy shows that (1) internal compressive and tensile stresses are generated on Ta and on Si substrates, respectively, and (2) the tensile stresses increase as the deposition time increases. Furthermore, when the films on the Si substrate were annealed, the Raman line shifted to a higher wave number as the annealing time increased, showing the reduction of the internal stresses.