The non-isothermal crystallization of poly(ethylene terephthalate) has been examined by temperature modulated differential scanning calorimetry (TMd.s.c.). A new analytical model of TMd.s.c. has been applied to the process, taking account of the response of exothermic heat flow to temperature modulation in an apparent heat capacity of complex quantity. By examining the frequency dependence of the apparent heat capacity, the applicability has been successfully examined for the non-isothermal process. The method is capable of determining the temperature dependence of crystal growth rate from TMd.s.c. data analysis. The results agree well with the dependence determined from literature values of spherulite growth rate measured by optical microscopy.