Barrel polishing device

A barrel polishing apparatus comprising a polishing space defined by a fixed tank having a predetermined axis as a center axis and a rotary disk disposed below the fixed tank and rotatable about the predetermined axis, wherein,

• the fixed tank includes a cylindrical rigid body and a first lining covering an inner circumferential surface of the cylindrical rigid body;
• the rotary disk includes a disk-shaped rigid body and a second lining covering a surface of the disk-shaped rigid body on the polishing space side, and is rotatably disposed in a state where a gap is formed between the first lining and the second lining;
• the disk-shaped rigid body includes a convex portion protruding toward the polishing space along the predetermined axis direction, a periphery of the convex portion being covered with the second lining;
• when viewed from a direction orthogonal to the predetermined axis, the convex portion overlaps the gap, and a length of a part of the convex portion overlapping the gap in the predetermined axis direction is one-third or more of a length of the gap in the predetermined axis direction;
• a retreat space is formed between the inner circumferential surface of the cylindrical rigid body and the first lining;
• the retreat space is formed at a position overlapping the gap when viewed from a direction orthogonal to the predetermined axis;
• a passage communicating with the gap and the retreat space is formed on a side opposite to the polishing space of the disk-shaped rigid body, and an elastic body for preventing polishing liquid from entering the retreat space is provided in the passage so as to cover an end portion of the retreat space on the passage side,
• an annular first flange fixed to the cylindrical rigid body is provided below the cylindrical rigid body, and
• the elastic body is fixed to the first flange via a second flange.