PURPOSE: To reduce contamination and drying irregularities of a body to a large extent, by freezing water droplets in drying the body, which is not yet dry, and sublimating the ice in a vacuum.

CONSTITUTION: A wafer 2 immediately after washing is put in a freezing chamber 1. When a valve 10 is opened, low temperature nitrogen gas is blown through a nitrogen-gas diffusion pipe 4, and water droplets on the wafer 2 are instantly frozen. The valve 10 is closed, and a partitioning door 7 to a vacuum chamber 5 is opened. Because of sudden reduction in pressure, ice component is sublimated (a), and contaminated material is also drawn in a vacuum. Since a valve 9 is opened intactly, the contaminated material and the water droplets are sucked with a vacuum pump, and the wafer 2 is completely dried without contamination again. The valve 9 is closed and nitrogen gas at normal temperature is blown through a nitrogen pipe 8. Thus the freezing chamber 1 and the vacuum chamber 5 are returned to the normal temperature. In this way, the contamination and irregularities of dryness of the wafer 2 are largely decreased.