Provided is a flow rate adjustment device, including: a storage tank that allows solid particles to be stored in the storage tank; a delivery pipe, which penetrates a bottom surface of the storage tank, and has an upper end arranged in the storage tank; a through hole, which penetrates a side surface of the delivery pipe, and guides the solid particles stored in the storage tank into the delivery pipe; an inclined portion, which is provided at an upper end of the delivery pipe, and is inclined downward toward an inner wall of the storage tank; and a foreign-matter receiving portion, which is formed in a region of the bottom surface of the storage tank, the region facing an edge of a lower end of the inclined portion, and which is recessed downward.