In an orthodontic device 10 according to the invention and an orthodontic attachment 11 includes an engaging portion 17 formed in a side portion of an archwire slot 16, and an orthodontic cap 13 is mounted ON the orthodontic attachment 11 while covering the whole of the archwire slot 16 and includes an engaging portion receiving portion 22 extending in a direction perpendicular to a mesiodistal direction of the archwire 12 and engageable with the engaging portion 17. In this orthodontic device, when retaining the archwire in the archwire slot of the orthodontic attachment, the archwire is retained by the orthodontic cap through the orthodontic attachment and thereby being able to reduction frictional resistance between the archwire and archwire slot. Also, this invention provides an orthodontic device and a method for mounting and removing an orthodontic cap which can provide an esthetic appearance because an orthodontic attachment and an archwire are covered with the orthodontic cap and can also facilitate the mounting and removing of the orthodontic cap with respect to the orthodontic attachment.
