FUEL SYSTEM AND VEHICLE

[Problem to be Solved] The present invention is to provide a fuel system and a vehicle which can improve mountability and assembly ease of parts. [Solution] A fuel system comprises a fuel storage source; a filling line adapted to connect the fuel storage source to a filling port; a supply line adapted to connect the fuel storage source to a fuel destination; a pressure reducing valve installed in the supply line; a first pressure sensor adapted to detect primary or secondary pressure of the pressure reducing valve; and an assembly which is an integration of the pressure reducing valve and the first pressure sensor. The assembly functions as a pipe fitting inserted in the supply line and has a line branch point for the supply line.