Suction device includes swirl flow-forming body that forms a swirl flow to apply suction to material by use of Bernoulli's principle, and case that houses swirl flow-forming body, and guides flow of a fluid flowing out of concave part of swirl flow-forming body. Case includes guide part, flange part, and cover part. Guide part controls flow of a fluid flowing out of concave part of swirl flow-forming body and flowing along end face, such that the fluid flows in a direction away from a position of material. Flange part forms, between flange part and end face, a flow path for a fluid to flow out of concave part. Cover part is fixed on the top surface of main body of swirl flow-forming body.
