To provide a flow rate selector so constituted that the material sealing the orifice in the flow rate selector can be used reasonably for a long period while maintaining in a natural flat-surface configuration and a fluid can be set to a predetermined flow rate.

This flow rate selector is equipped inside with a web having the flat surface on which at least two seals are arranged so that it can come into close contact with the flat surface having orifices of two different cross sections. By rotating the flow rate selector knob relative to the flat surface having the orifice and aligning one side of the seal with either of the orifices, the fluid is prevented from passing through the orifice and it is made possible to pass the fluid through the orifice of another side.