The present invention is to provide an attachment device of a display panel capable of, while solving enclosure of bubbles in an attachment surface at the time of attachment, reliably removing bubbles generated even after attachment, and remarkably lowering a defectiveness ratio of an attachment body to improve productivity of attachment tasks. A vacuum chamber unit 3 is formed by a chamber main body 10 and a chamber lid body 11. A fixed attachment base 12 including a dam jig 13 is provided in an interior of the chamber main body 10, and a movable attachment base 16 is provided in an interior of the chamber lid body 11. After a display panel P1 and an object to be attached P2 loaded to the dam jig 13 and the movable attachment base 16 are attached under a vacuum environment, the vacuum chamber unit 3 is brought into an inclined posture by a chamber inclination device, a non-sealed portion 34 not sealed by the dam jig 13 is placed at an inclination upper end of the display panel P1, and bubbles generated on an attachment surface in a process of hardening an adhesive are removed from the non-sealed portion 34.