ports h 2 which are provided on the suction surface n side fig1 shows a configuration in which three injection ports h 2 are provided each of the three injection ports h 2 communicates with one inflow port h 1 in addition the three injection ports h 2 are arranged so as to be separated from each other from the inside in the radial direction of the disk 2 toward the outside in the radial direction that is three channels are formed inside the hole h toward the injection ports h 2 with the inflow path h 1 as the starting point in addition the channel which is positioned in the innermost side in the radial direction among the three channels linearly communicates with the inflow port h 1 according to this configuration after the jet stream fj introduced from one inflow port h 1 is divided into three streams toward the three channels the divided jet stream is injected from the three injection ports h 2 to the suction surface n side accordingly it is possible to supply the jet stream fj to the suction surface n side in a wide range moreover since only one inflow port h 1 is provided on the pressure surface p side the components of the flow extracted from the main stream f.