The purpose of this study is to analyze the effect of sunshine on the heating energy consumption of apartment houses by a field investigation in Haeundae, Busan. In the field, heating energy consumption of every household is researched by reading a calorimeter and the duration of sunshine of every household is calculated by Sunlight V1.0. Then, the duration of sunshine and heating energy are done regression analysis by SPSS 10. According to this study the apartment houses by orientation spend more energies order of east, west, southeast, southwest, and south. When apartment houses are same orientation, there is difference of $29{sim}58\%$ in heating energy consumption by the duration of sunshine. And the heating energy consumption in worst condition of sunshine increases $67\%$ on the best condition of sunshine.