  We present an accurate analytic fitting formula for the thermal
bremsstrahlung Gaunt factor in the nonrelativistic limit. The fitting formula
excellently reproduces the numerical results of the calculation carried out by
the present authors using the method of Karzas and Latter. The present analytic
fitting formula will be useful for the analysis of the X-ray emission which
comes from the intracluster plasmas with relatively low temperatures as well as
the other X-ray sources.
