Following results are derived from the analysis of statistic data for 10 years from 1959 to 1969 to explain the factors affecting periodical cycle in hog production. 1. Hog production shows periodical cycle ranging 3 years. For example, hog production remains the lowest degree in 1961, 1964 and 1967. 2. When farmers` selling price of hog and price of pork were established very high in a certain year, hog production of the following year used to increase, and vice versa. However, the significance of correlation coefficient between hog production were not confirmed. 3. The significance of correlation coefficient among feed price, export quantity, competitive goods (beef, chicken) and butchering hogs was not confirmed. 4. Though we can suggest that such factors as butchering hogs, pork price and hog production are correlated to make the periodical cycle in hog production, the correlation coefficient are not explained plainly owing to unaccurate statistics of butchering hogs. Many hogs are butchered illegally.