PURPOSE: To enable the conveyance of powder through a conveyor employing a flexible spiral member, by providing projections or eccentric portions on the peripheral part of the spiral member to break the adhering layer of the conveyed material and using the revolution of the projections or eccentric portions to prevent the growth of the adhering layer.

CONSTITUTION: A spiral member 2 for conveyance is inserted into a flexible and bendable pipe 1. An outlet port 3 is provided in the upper part of the bendable pipe 1. A hopper is provided at the lower part of the pipe. A driver is installed over the outlet port 3. A bolt 7 for clamping the end of the coil 2 is secured on the drive shaft 6 of the driver. Small projections 9 are provided on the peripheral part of the spiral member 2 to breack an adhering layer 10 of powder. The adhering layer 10, which is made of the powder being conveyed upward in the bendable pipe 1 by the spiral motion of the spiral member 2, is broken by the projections 9 with the tridimensional movement of the member 2.