A freeze drying device mainly comprises a machine body arranged with a drying chamber, a vacuum unit, a condensing unit, and a frame and a control circuit installed in the drying chamber; and a touch screen. The freeze drying device is provided for preservation of drug and food and for objects, of which the original flavor is to be kept and which are sensitive to temperature and perishable, without destroying tissue and deteriorating. The object is first frozen and air is evacuated to form vacuum. Then, first and second stages of drying is applied to remove water from the interior thereof under a negative pressure, so as to keep complete nutrition and original shape, size, color and structure. The operating steps are directly controlled and set for activation through the touch screen. The status of the operation is displayed on the touch screen. A test operation can be conducted through the touch screen to display related data and records as reference operating error.