PURPOSE: To carry out smooth delivery of material by providing a delivering conveyor rotatably as well as retractably from the inside and outside of the delivering outlet of a circular silo.

CONSTITUTION: In the lower part of a circular silo 1, an annular delivering outlet 2 centering around the central axis (a) of said silo 1 is opened, and a material discharge stopping 3 is formed beneath the outlet 2. And, a delivering screw conveyor 6 which is thrustable and retractable from the delivering outlet 2 is provided on a unit frame 5 which is rotatably supported sround the central axis (a). Therefore, the end part of the delivering screw conveyor 6 can be thrusted and retracted from the inside and outside of the annular delivering outlet 2, while the end part can moved along the delivering outlet 2 while being kept thrusted into it. Thereby, material 11 in the circular silo 1 can be delivered continuously and uniformly and, in accordance with the thrusting length of the end part into the delivering outlet 2, the delivering quantity of the material can be adjusted quite easily and smoothly.