In this study, the conditions under which "stop-and-go approximation" applies to FMCW SAR are analyzed. We analytically verified that the validity of stop-and-go approximation is generalized in Ku-band frequency modulated continuous wave (FMCW) synthetic aperture radar (SAR). SAR processing time reduces without degrading the SAR image quality by applying stop-and-go approximation. Point target simulations are performed to provide quantitative results supporting the above argument.