To provide a plug device preventing rattling upon being fitted to a lock device body without the need for a separate rattling preventing means in the lock device body.

The plug device for providing the lock device body 1 with a rotary operation part by insertion into a cylindrical fitting part 2 formed in the lock device body 1 includes: a plug 3; a sleeve 4 externally fitted to the plug 3 in an idling and axially movable manner; and an elastically urging part 5 interposed between the plug 3 and the sleeve 4 to elastically urge the plug 3 in a pushing-back direction upon fitting of the plug 3 to the cylindrical fitting part 2.