Abstract: An apparatus and method are disclosed that can process a substrate such as a wafer while keeping high cleanliness. The apparatus comprises a center port 100, which is stationarily arranged in the center and on the surface of which at least one blow-off outlet is provided for blowing off fluid, and a rotating housing portion 200 which is capable of rotating about the center port 100. The rotating housing portion 200 comprises a top plate 210 comprising a main surface S2 that opposes a wafer W, and a lower housing being connected to the top plate 210 and rotatably driven by a rotation-driving member. When the surface S1 comprising blow-off outlets 151a and 153a of the center port 100 is offset from the main surface S2 of the top plate 210 and fluid is blown off from the blow-off outlet 151a, the substrate W is contactlessly held above the main surface S2 of the top plate 210 and the surface S1 of the center port 100.