PURPOSE: To cope with restrictions specified by the explosion proof regulation so as to simplify an entire structure of a rake-out device by adjusting the depth of encroaching of a rotary rake-out arm into a bottom of a storage container for pulverulent bodies by way of a drive-away outlet while the number of revolution is kept constant.

CONSTITUTION: A rake-out arm 15 is allowed to rotate at a constant number of revolution by means of an electric drive motor 16 installed on a travel truck 11. In this condition, the travel truck 11 is allowed to move back and forth within a range between a position just before the rake-out arm 15 is inserted into a drive-away outlet 13 and a position where the arm is inserted in deeply to the back of the outlet in response to the amount of materials to be driven away. Consequently, the back and forth movement of the travel truck 11 allows the depth of encroaching by the rake-out arm 15 into the bottom of a storage container for pulverulent bodies to be adjusted through the drive-away outlet 13. Thus, this configuration enables the amount of pulverulent bodies in the storage container to be adjusted when it is driven away from a hopper 11 and the drive-away outlet 13 of a table 12.