The transfer chamber transfers a wafer (W) as a transferred object to or from a processing device (6) by using a transfer robot (2) provided thereinside, and includes a circulation path (CL) formed inside of a transfer chamber (1) to circulate gas, a chemical filter unit (7) as a chemical filter provided in the midstream of the circulation path (CL), a humidity detector (HG2) as a humidity detection means which detects internal humidity, a gas supply means (NS) which supplies gas to the inside of the transfer chamber (1), and a moisture supply means (HS) which supplies moisture content to the inside of the transfer chamber (1). The moisture supply means (HS) is made to operate in accordance with a humidity detection value by the humidity detection means.