A capping device includes a moisturizing cap which is brought into contact with a liquid ejecting unit configured to eject a liquid from a nozzle so as to allow forming of a space including the nozzle, a connection flow channel which is connected to the moisturizing cap, and a moisturizing liquid supply unit which is connected to the connection flow channel, includes a moisturizing liquid storage unit configured to allow storing of a moisturizing liquid, and allows a supply of the moisturizing liquid to the moisturizing liquid storage unit so as to cause a liquid surface of the moisturizing liquid in the moisturizing liquid storage unit to be a first position. The moisturizing cap includes an atmospheric communication portion configured to open the space to an atmosphere.