To solve the problem in the bent pipe part wherein in a complicated passage for passing a fluid in a pipeline, when the fluid passes through the pipeline, elongation, vibration, temperature, pressure, impact force and deformation have a little influence upon the pipeline, as sometimes it is necessary to provide bent pipe parts in several places, the bent pipe part where the passage is changed has a tendency of remarkably amplifying stress due to vibration, pressure and temperature difference of the fluid, as the temperature of the fluid in the pipe is not always constant, the influence of the temperature difference of the fluid upon the life of the pipe can not be ignored, in the bent pipe part of the pipeline, the pipeline is deteriorated due to elongation always caused in the pipeline by the vibration and temperature difference of the fluid, so that very small cracks cause an unexpected situation, and most of cracks are cracks generated in the bent pipe part.

In this fluid control device of the bent pipe part, a control pipe 5 is connected to a part of a pipe on this side of the bent pipe part, a straightening plate 7 is provided on one side in the control pipe, a rotary plate 8 is provided on the other side, and the control pipe 5 is connected to the bent pipe part 6.