a fluid pump has a rotary pressure generator means rotatingly driven by a power unit , such as an automotive engine , and variable of output pressure depending upon rotation speed of the power unit . the pressurized fluid output from the pressure generator means is supplied to a high pressure chamber which is connected to an external hydraulic device , such as an automotive steering device , via a high pressure path and a supply line . the supply line is connected to a high pressure path via a pressure regulating path . the pressure regulating path is so designed as to provide flow resistance which increases according to increasing of the fluid pressure supplied to the supply line from the high pressure path . this makes pressure variation gradient at the supply line smaller than that in the high pressure path .