IN 617 was crept under stresses of 107 and 180 MPa with monotonic deformation to strains of $varepsilon$= 0.03 - 0.30 at 1073K. In order to determine the distances between the subgrain boundaries, the deformed specimens were examined at magnifications of one hundred thousand times by TEM. In cases . where TEM observations were not possible, subgrain angles($ heta$_{s}=sin^{-1}$(b/s))were measured by Kikuchi diffraction lines. The $ heta$_{k}$</TEX> converted from s values measured directly by TEM agreed very well with those measured from Kikuchi lines. Therefore, it was found that the $ heta$_{k}$ values could be used in obtaining s, especially in cases where it is impossible to measure s by TEM.