To restrain leakage of fuel vapor from a fuel tank of a vehicle fuel system by providing a module installed in the fuel tank with a vapor discharge valve, fuel pump, fuel level transmitter, excessive pressure relief valve, outlet and the like, in such a manner that it is stored in the tank through one hole.

A module 10 stored in a fuel tank of a vehicle fuel system through one hole formed in a ceiling surface of the tank comprises a fuel pump 14, an upper end cap 34 provided with a rotary vapor discharge valve and an excessive pressure relief valve, a fuel level transmitter, and the like, which are integrated with each other. The pump 14 has at its lower part an inlet 24, through which fuel is filtered and suctioned to a pump assembly 26, and then the fuel increased in pressure is discharged from an outlet 28. An electric motor 30 is driven with electric power supplied from the outside of a fuel tank 12 through an electrical connector 32 for driving the assembly 26.