A transfer device is disposed in a vacuum transfer chamber. The transfer device includes a structure body having an inner space isolated from the vacuum transfer chamber, an arm that rotates with respect to the structure body, and a vacuum seal structure configured to airtightly seal a sliding portion between the structure body and the arm. Further, the vacuum seal structure includes one or more seal members disposed at the sliding portion; a sealing portion formed by the structure body, the arm, and the seal members, lubricant being sealed in the sealing portion; and a pressure adjusting unit configured to adjust a pressure in the sealing portion.