A fuel injection controller includes a correcting section that performs a concentration learning procedure in which a concentration of the alcohol of the fuel in a fuel tank is learned as a learned concentration value based on a detection value of the oxygen concentration sensor, and also corrects a fuel injection amount of an injector connected to a delivery pipe in correspondence with the learned concentration value in such a manner that an air-fuel ratio corresponding to a stoichiometric air-fuel ratio is obtained. A refueling detecting section detects that refueling has been carried out to the fuel tank, and a restricting section performs a restricting procedure in which returning of the fuel from the delivery pipe to the fuel tank through a return passage is restricted on condition that the refueling detecting section has detected that the refueling has been performed.