PURPOSE: To inhibit sublimation of a target sublimable material to be purified accompanying the sublimation of sublimable impurity by the operation at ordinary temp. by providing a collecting device interposing a reducing mechanism to a discharging pipe connected to a vessel for the sublimable material.

CONSTITUTION: Sublimable materials A to be purified contg. a sublimable impurity B is contained in a vessel 10 and discharged to a discharging pipe 11 at ordinary temp. under normal pressure. The amt. to be discharged is limited by a reducing mechanism 13, and purified sublimable material A alone is separated by liquefaction in a collecting device 14 cooled by a cooling and heating mechanism 14a. Further, the purified sublimable material A alone contained in the gas remaining after separation is recovered by condensing again in a recovering device 4, and the sublimable impurity B is discharged by an exhausting device 5.