To provide a rotation device by which the size of a device body can be reduced and the rotatable angle range of a rotating body can be sufficiently secured.

An operation device includes the rotating body 40 rotatably supported by a casing, and a link body 17 for connecting the casing and the rotating body. The link body 17 includes a first connector 50 and a second connector 60, and can be expanded and contracted freely by the relative movement of the first connector 50 and the second connector 60 in a depth direction 33. An end of the first connector 50 is slidably and rotatably held on the rotating body 40 between the first position 21 and the second position 22. An end of the second connector 60 is rotatably held on the casing. The link body 17 widens the rotatable angle range of the rotating body 40 by being elongated.