In preparation of steamed foam cakes by separated-egg-sponge method, effects of whipping time ($X_1$, 4-12 min), quantity of wheat flour ($X_2$, 460-540 g), and number of folding ($X_3$, 110-190 times) of the steamed foam cakes were investigated using response surface method. Measuring $R^2$ of the volume and hardness were 0.9094 and 0.9119, respectively at p<0.05 and gumminess and chewiness were 0.9397 and 0.9429, respectively at p<0.01. According to the result of examining the effect of independent variables on each reaction variable, physical properties was affected most significantly by whipping time. According to the result of examining the response surface graphs and the optimal condition of ordinary points, volume showed a maximal point, hardness a minimal point, and all the other items a saddle point. The experimental results for optimum manufacturing conditions for separated-egg-sponge method, i.e., 7.5 min whipping time, 492 g amount of wheat flour, and 149 times number of folding were empirically proven to fit the predicted levels of physical properties from the final foam cakes.