This study has been performed to develop a program which can help the management of the entrusted farming company(EFC). An algorithm for machinery cost estimation and computer programs were developed and those were tested with sample data of EFC for the fm size of 50 ha. The results of the test showed for the farm size of 50ha that tillage cost was 18, 785 thousand won ; 23, 441 thousand won for the transplanting, 24, 904 thousand won for the combining, and 4, 024 thousand won for drying. An algorithm for the critical entrusted In analysis and a computer program were developed and those were tested with data estimated. The results showed that tillage fee was 376 thousand won per ha, 496 thousand won for transplanting 495 thousand won for combining and, 32, 480 won per ton for drying. The algorithms and a computer program were developed for the analysis of the critical optimum working area when the entrusted working fee was provided.