Abstract: An automatic selector valve including a box body having an internal space portion, framed partition plates separating the space portion into four rooms, each framed partition plate having an opening portion, plate-shaped turnable valve bodies opening or closing the opening portions of the framed partition plates, an inflow port letting a gas flow in, an inflow/outflow port letting a gas flow in and flow out alternately, an outflow port letting a gas flow out through, and an inflow/outflow port letting a gas flow in and flow out alternately with the port, the ports provided in the separated four rooms, and a driving mechanism turning the plate-shaped turnable valve bodies about a rotation shaft.

Abstract: Provided is an automatic four-port selector valve which is capable of controlling a variation in static pressure and a variation in flow rate induced in the switching of air or gas flow passages so that they are within tolerant accuracies, which is further capable of controlling a saliently appearing variation in pressure difference in a clean temperature-controlled/humidity-controlled air supply apparatus, a dry air supply apparatus, etc.