A fuel injection controller includes an oxygen sensor that responds to an oxygen concentration inside an exhaust passage, and an injection amount control unit programmed to control a fuel injection amount based on the output of the oxygen sensor. The injection amount control unit includes an injection amount correction value computing unit that determines an injection amount correction value based on the output of the oxygen sensor, a short-time learning value computing unit that determines a short-time learning value based on the injection amount correction value, a long-time learning value computing unit that determines a long-time learning value based on the short-time learning value; a feedback correction amount computing unit that computes a feedback correction amount, an injection amount control value computing unit that computes a control value of the fuel injection amount, and a long-time learning value holding unit that holds the long-time learning value.