PURPOSE: To prevent fall of deposited metal in opening and closing operation of a cell shutter by energizing the heater of this cell shutter to raise the temp. of the cell shutter and to evaporate the deposited metal at the time of opening the shutter.

CONSTITUTION: This cell shutter 29 is used for passing and shielding of molecular beams of a molecular beam crystal growth apparatus and consists of the cell shutter 29 including the heater 34 which does not heat the cell shutter 29 in the closing state of the cell shutter 29 automatically and heats the cell shutter 29 at the time of opening the cell shutter. As a result, the decrease in the reflection effect of the heat reflection plate of the cell shutter is prevented and the contamination of the metal in a crucible is prevented. In addition, the evaporated metal at the time of closing the shutter is deposited on the cell shutter, by which the contamination of the evaporated metal in the crucible by reflection is prevented.