Temperature-dependent development of Carposina sasakii Matsumura was studied, and its stage emergence models were developed. The development times of C. sasakii decreased with increasing temperature up to 32°C in eggs, up to 28°C in larvae, and up to 30°C in pupae. The estimated low-threshold temperatures were 11.0, 9.4, and 10.3°C for eggs, larvae, and pupae, respectively. Thermal constants of eggs, larvae, and pupae were 104.2, 270.3, and 188.7 degree-days, respectively. The stage emergence models of C. sasakii, which simulate the proportion of individuals shifted from a stage to the next stage, were constructed using the modified Sharpe and DeMichele model and the two-parameter Weibull function. In field validation, a degree-day model for the prediction of egg hatch time showed the bias of <1 d between prediction and observation. The stage emergence models predicted the patterns of C. sasakii stage emergences in the field. Also, the established stage emergence models should be useful in building a C. sasakii population model that will describe its seasonal occurrence pattern and population dynamics under various orchard systems.