A fuel system for a vehicle with an engine includes: a fuel tank for storing fuel: first and second ports disposed on a wall of the fuel tank, between which wall and a fuel fluid level a clearance is created when the fuel is contained in an allowable maximal amount in the fuel tank of the vehicle in a horizontal state, the first and second ports being positioned frontward and rearward, respectively, in a longitudinal direction of the vehicle, and the first port and the second port being out of alignment in a lateral direction; a canister for adsorbing and releasing a fuel vapor; an inflow line for sending the fuel vapor generated in the fuel tank to the canister through the first and second ports; and a discharge line for sending the fuel vapor from the canister to an air-intake path to the engine.