A fuel injection controller for a vessel engine to drive a propulsion apparatus mounted in a vessel is configured or programmed to execute functions of an effective opening area calculator to calculate an effective opening area of a throttle valve based on a throttle opening degree of the vessel engine, a filter value calculator to determine a first-order lag filter value of the effective opening area, a correction value calculator to determine a ratio of the effective opening area to the first-order lag filter value as a correction value, a predictive suction pressure calculator to determine predictive suction pressure by multiplying an average value of suction pressure detected at a suction passage by the correction value determined by the correction value calculator, a fuel injection amount calculator to calculate a fuel injection amount based on the predictive suction pressure, and a fuel injection driver to drive a fuel injector based on the fuel injection amount.