Plug fluid transfer coupling device

By linking together the socket (10) and the plug (70), internal passage (78 plug socket and a fluid transfer coupling device for communicating with each other the respective flow paths of the plug (5) is, the fluid passes through ) and the inner spacer (74) which is formed, a plug collar covering an outer peripheral surface of the inner spacer (73), a flange (75) which provided in the proximal end of the plug connecting the plug to the conduit having at least a. The plug collar and the flange are formed of metal. Thus, to the plug even when the flow rate of the fluid is large it is firmly supported. The inner spacer is formed from a resin material. At least a portion of the outer peripheral portion of the plug may be formed of metal.