A conveyor device comprising: - a curved passage part; - a circular plate body; and - a rotating unit for rotating the circular plate body, wherein a part of the circular plate body is located in the curved passage part to constitute a conveying surface of the curved passage part, wherein the rest part of the circular plate body located at a position other than the curved passage part is shielded by a linear conveyor (2, 5), and wherein the curved passage part comprises: - an object introducing part where the rotating circular plate body appears in the curved passage part from a position shielded by the linear conveyor; and - an object discharging part where the rotating circular plate body is housed into the position shielded by the linear conveyor from the curved passage part, wherein each of the object introducing part and the object discharging part is provided with the linear conveyor (2, 5), the two linear conveyors (2, 5) being parallel to each other, each of the linear conveyors (2, 5) being adapted to conveying the object by a rotation body or a traveling body, wherein the circular body plate is made from metal, has a thickness that is extremely thinner than the diameter thereof and is easily bent, wherein the curved passage part includes an outer frame, an inner frame, the circular plate body and the rotating unit, wherein the outer frame is bent into a circular arc shape of 180° in a plan view, wherein the outer frame comprises a flange and a web, wherein the rotating unit is a motor-incorporating roller, wherein the conveyor device further comprises a follower roller in contact with an upper face of an outer peripheral edge of the circular plate body, wherein the follower roller is attached to the flange of the outer frame at a position above the motor-incorporating roller, wherein the outer peripheral edge of the circular plate body is held between the follower roller and the motor-incorporating roller, the circular plate body being elastically deformable, and wherein the part shielded by the linear conveyor (2, 5) is tilted with respect to the part located in the curved passage part and is adapted to get under the linear conveyor (2, 5). - a curved passage part; - a circular plate body; and - a rotating unit for rotating the circular plate body, wherein a part of the circular plate body is located in the curved passage part to constitute a conveying surface of the curved passage part, wherein the rest part of the circular plate body located at a position other than the curved passage part is shielded by a linear conveyor (2, 5), and wherein the curved passage part comprises: - an object introducing part where the rotating circular plate body appears in the curved passage part from a position shielded by the linear conveyor; and - an object discharging part where the rotating circular plate body is housed into the position shielded by the linear conveyor from the curved passage part, - an object introducing part where the rotating circular plate body appears in the curved passage part from a position shielded by the linear conveyor; and - an object discharging part where the rotating circular plate body is housed into the position shielded by the linear conveyor from the curved passage part, wherein each of the object introducing part and the object discharging part is provided with the linear conveyor (2, 5), the two linear conveyors (2, 5) being parallel to each other, each of the linear conveyors (2, 5) being adapted to conveying the object by a rotation body or a traveling body, wherein the circular body plate is made from metal, has a thickness that is extremely thinner than the diameter thereof and is easily bent, wherein the curved passage part includes an outer frame, an inner frame, the circular plate body and the rotating unit, wherein the outer frame is bent into a circular arc shape of 180° in a plan view, wherein the outer frame comprises a flange and a web, wherein the rotating unit is a motor-incorporating roller, wherein the conveyor device further comprises a follower roller in contact with an upper face of an outer peripheral edge of the circular plate body, wherein the follower roller is attached to the flange of the outer frame at a position above the motor-incorporating roller, wherein the outer peripheral edge of the circular plate body is held between the follower roller and the motor-incorporating roller, the circular plate body being elastically deformable, and wherein the part shielded by the linear conveyor (2, 5) is tilted with respect to the part located in the curved passage part and is adapted to get under the linear conveyor (2, 5).