To improve a fault of conventional pilot valve type electromagnetic feed water valve unit, in which a flow detect device for enabling detection of a flow rate cannot be incorporated without altering the outward appearance of the feed water valve unit.

An inflow port 11, inflow pass 12, inflow room 13, discharge pass 14 and discharge port 16 are formed integrally into a valve body 17. A main valve seat 15 formed like a lip packing is fit tightly to the discharge pass 14, and an impeller 23 having a magnet 22 is located onto the main valve seat 15 as the axis, in the inflow room 13, and a magnetic detector 24 is provided on the peripheral of the valve body 17, to constitute a pilot type electromagnetic feed water valve unit.