A flow-controlling unit having a function of limiting the tilting angle of a flow-controlling piece is disclosed. The flow-controlling unit having a function of limiting the tilting angle of a flow-controlling piece, according to one embodiment of the present invention, comprises: a flow-controlling plate, which is disposed perpendicular to the moving direction of a fluid in a flow channel, and on which are formed one or more first fluid through-holes through which the fluid passes, and on which flow-controlling pieces are formed which are provided in a part corresponding to the first fluid through-holes, are inclined in the direction of the inflow of the fluid, are capable of tilting, and control the degree of opening of the first fluid through-holes by being tilted due to pressure applied from hydraulic pressure of the fluid; and a tilting-angle-limiting plate, on which are formed second fluid through-holes which communicate with the first fluid through-holes, wherein the diameter of the second fluid through-holes is smaller than the diameter of the first fluid through-holes, allowing the flow-controlling pieces to be supported so as to limit the tilting angle of the flow-controlling pieces.