A rotary valve comprising sliding members for supplying treatment gas containing water vapor to a plurality of treatment processes is provided. The rotary valve comprises sliding members (1, 2 4, 6), through which open flow passages (8, 9, 10), having sliding surfaces slidable to each other and a mechanical seal mechanism for switching the flow passages (8, 9, 10) while sealing fluid by preliminarily pressing the sliding surfaces, wherein the sliding surface of each sliding members (1, 2 4, 6) is made of hydrophobic material (2, 4) different in hardness from the other.本發明係提供一種具有用以將含有水蒸氣之處理氣體供給至多數處理步驟中之滑動構件之旋轉閥。本發明之旋轉閥,係包含有:滑動構件,其流路具有開口且設有可相互滑動之滑動面;及機械密封機構,可藉由一邊對前述滑動面施壓以密封流體一邊滑動,以切換前述流路,且前述滑動構件之滑動面側由硬度不同之疏水性構件構成。1,2...固定構件3,5...接著面4,6...旋轉構件7...旋轉軸8...氣體供給口(孔口)9...分配槽(連結流路)10...氣體出口(孔口)
