A drying machine for discarded Citrus scrap was developed in this study. The Citrus produced in Jeju Province was treated as wastes (a) after making a beverage, such as drinking juice, and (b) if the size of the product did not fit with its agricultural product criteria. Various types of drying machine were developed in this study, and different kinds of technologies were combined improve the performance. To enhance the performance, the system was maintained in a vacuum state, and a high frequency micro wave was activated to the waste Citrus scrap, to heat up the moisture inside the Citrus kernels. The frequency of the micro-wave was 2.6 GHz, which is the resonant frequency of the molecules. Experiments were conducted with a vacuum of 50, 100, 150, 300, 500, and 700 mbar. The waste Citrus scrap has two types of status : (a) original scrap, and (b) mixed with blender. As results, specimen (a) shows a 0.13 g/sec evaporation rate, while specimen (b) shows a 0.19 g/sec rate, at 50 mbar of environment vacuum condition. For the drying efficiency, specimens (a) and (b) show 0.15 g/W and 0.24 g/W, respectively.